Component Engineering Training Course VF No. 1 Component Engineering Training Course This Training Course has been compiled and is presented by Spur Electron

Component Engineering Training Course VF No. 1

Component Engineering Training Course

This Training Course has been compiled and is presented by Spur Electron Ltd.


WHAT IS COMPONENT ENGINEERING?

It is an individual or group which provides the project team with a broad knowledge and experience of EEE components, including:

• Electronic and semiconductor theory and principals

• Materials, construction and manufacture

• Space component procurement systems

• Quality and screening requirements


HIGH RELIABILITY COMPONENTS

DEFINITION : A component is defined as :-

The smallest sub-division of a system which cannot be further sub- divided without destroying its function.

EEE stands for :-

E Electrical, e.g. Resistors, Capacitors, Connectors

E Electromechanical, e.g. Relays, Switches, Actuators

E Electronic, e.g. Integrated Circuits, Transistors, Diodes


HIGH RELIABILITY COMPONENTS (CONT.)

Europeans tend to use the word “Component”, whereas the Americans use the term “Part”. Both terms will be found within this presentation, and should be considered as synonymous.

Europeans use the term “High Reliability Components, Americans often use the term “Hi-Rel Part”. Again the terms are synonymous.

High Reliability components are those in which a very high degree of confidence can be placed that they have stable characteristics and a working life in excess of the mission requirements.

This definition is flawed, in that the components are manufactured to a standard set of requirements, whilst mission duration's vary considerably.



A decade ago mission duration's were typically 3 to 5 years. Today mission duration's of up to 15 to 20 years are required.

The US Military market has led the field in specifying reliability standards.

In the mid 1960’s, various government agencies identified that defects, able to be screened out, were resulting in an equipment failure rate of about 1% per thousand hours.

In-depth failure analysis identified the predominant failure mechanisms.



The Solid State Applications Branch of the RADC was assigned the task of developing a screening procedure to remove the infant mortality failures, which led to the high failure rates previously encountered.

In 1968 the RADC staff developed MIL-STD-883.


THE BATHTUB CURVE

Time in operation

Phase I

InfantMortality

Phase II

Working Life

Phase III

Wear-Out

FailureRate


OPERATING ENVIRONMENT FOR SPACE COMPONENTS

Environmental Extremes:

• Temperature

• Radiation

• Mechanical Stresses

• Vacuum


THE EUROPEAN APPROACH TO SPACE COMPONENTS


ORIGINS OF THE ESA/SCC SYSTEM

Need for Pan-European Specification System for EEE Components realized by ESRO, prior to the formation of ESA.

Until this need was recognized and acted upon a range of differing specification systems were being used


ORIGINS OF THE ESA/SCC SYSTEM (CONT.)

This resulted in:

- No standardization.

- Wide variations in test and inspection philosophies.

- Huge variances in manufacturers quoted price and delivery.

- Extreme difficulty in assessing comparative quality and reliability of delivered components.



In 1971 ESRO through its Joint Programmes and Policy Committee (JPPC) set up the Space Components Coordination Group (SCCG) on an interim basis as an advisory group.

Over 30 years later, this interim group is still operating.

In 1973 the JPPC approved the SCCG Terms of Reference.

The SCCG now set about the generation of a series of basic policy documents.



These documents were approved by the SCCG at its plenary meeting in November 1973 and submitted to the JPPC for its approval.

Before approval by the JPPC, ESRO and ELDO were merged into the present day ESA.

ESA then abolished the JPPC, and the SCCG was placed under the direct authority of the Director General.



This new status entailed new terms of reference and redefinition of responsibilities for both the SCCG and the Director General.

The placement of the SCCG under the Director General's control was finally approved in 1976.

This ESA policy has been superseded by ESCC and SCAHC


OBJECTIVES OF THE ESA/SCC SYSTEM

The basic objectives of the ESA/SCC System as defined by ESA/SCC Document No. 00000 “Object and Basic Rules of the ESA/SCC System” are:

- Political. The promotion of a European System of

Specifications for Space Components.

- Technical. The System capable of being integrated

with other international systems.

- Commercial. Promotion of the production in Europe of Components suitable for Space Application.


OBJECTIVES OF THE ESA/SCC SYSTEM

- Standardisation

- Interchangability

- Improvement cost/schedule planning


SCCG ACHIEVEMENTS

By the early 1980s the SCCG had achieved a very complete ESA/SCC System comprising over 1000 specifications and had assisted in the qualification of some 350 components manufactured by a total of 40 European manufacturers.

In spite of this success the European user community were very concerned that ESA/SCC components were significantly more expensive than space qualified components from the US.

There was also a major concern that the SCCG was overly bureaucratic and the ESA/SCC System over specified technical requirements.

In 1993 ESA published a technical paper recommending some major areas of review and modification.

This lead to the formation of SCAHC.


SCAHC

What was SCAHC?

- The Space Components Ad Hoc Committee (SCAHC) was established by ESA in October 1994

- It comprised of experts from all the main space sectors within Europe. i.e. ESA, National Space Agencies, Commercial Space Organisations, Space Industry and Space Component Manufacturers. In addition the European Commission was also represented.

- The SCAHC task was to formulate a long term programme for space components that would enhance European competitiveness in the world market.


SCAHC RECOMMENDATIONS

In a final report released in 1995 the SCAHC made ten recommendations:

R1 – Maintain the ESA/SCC System of specifications including related qualification programmes and quality assurance approach in order to meet users needs and market trends.

R2 – Standards and specifications for components shall reflect a higher degree of delegation from suppliers with reduced customers controls.

R3 – Wherever possible, European component specifications and standards should be based on international standards and should be promoted to obtain international recognition.


SCAHC RECOMMENDATIONS (CONT.)

R4 – Implement a stringent system for the reduction of diversity of components for use in space, based on the usage of a European Preferred Parts List, giving preference to European components.

R5 – Establish a reliability system for European space Components

R6 – Establish an information Exchange system on component data with access for all European users.

R7 – Enable the mutual recognition of industrial performance in the various component disciplines, including component engineering, radiation hardness assurance, auditing and inspection (with formal certification of the latter), through provision of the relevant and regular training opportunities.


SCAHC RECOMMENDATIONS (CONT.)

R8 – Improve the availability of strategically important components, giving preference to European sources (Microprocessors, MMICs etc).

R9 – Implement, in full partnership with the users, manufacturers, commercial customers and agencies, a European Space Component Research and Technology Programme assuring coherence with other market sectors, and cost effectiveness.

R10 – Establish a permanent Component Steering Board (CSB) representing the interests of all the European space partners, to monitor market trends, to provide financing and to overview the technology programmes and its synergies, and advise on necessary policy changes.


SCSB ACHEIVEMENTS TO DATE

In the 7 years since the SCAHC recommendations were made progress has been slow but reasonably successful.

Using the recommendations as a guide we can demonstrate the following achievements.

R1 Maintain but improve the ESA/SCC system.

Two major contracts awarded. One to review the structure and organisation, relatively successful, the SCSB now responsible for the policy and the Executive responsible for the day to day operation.

Second contract to carry out in depth review. Results very controversial. However general agreement appears to have been reached, some changes already incorporated, some still to be made.


ACHEIVEMENTS TO DATE (CONT.)

R2 Reduce Customer Controls.

Partially achieved by the reduction of deliverable documentation, now incorporated into the system.

R3 Gain international recognition for the system

NASA now accept ESA/SCC Level B as equivalent to US MIL Level S

R4 Establish a European PPL

Now available on ESCIES (see later)

R5 Establish a European reliability system

Problem found to be an international concern. NASA and NASDA are currently involved in seeking solutions.

R6 Establish Information Exchange Database

Now Established (see ESCIES).


ACHEIVEMENTS TO DATE (CONT.)

R7 Enable mutual recognition.

Set of training programmes envisioned. Still not fully initiated.

R8 Improve availability of strategically important components.

Incorporate into CTB activities, see R9 below.

R9 Establish a Component Technology Board.

The CTB is well established and has developed it’s own five year plan. However funding availability is a major concern.

R10 Establish a Space Components Steering Board (SCSB).

SCSB Charter was formally signed on 8th October 2002


MR. RODOTẦ SIGNS THE CHARTER


ESA/SCC STILL THE STANDARD

Even though the ESCC is intended to replace the ESA/SCC System, it hasn’t yet happened and is unlikely to be complete for a number of years. In the meantime the ESA/SCC System continues to be the preferred standard.


RELATIONSHIP TO THE ECSS SYSTEM

The ESA/SCC specification system is a self contained subset of the ECSS System in that ECSS-Q-00 identifies that components shall be procured by means of the ESA/SCC specification system, thus making it a part of the ECSS system.

ECSS-Q-60 is the Level II document applicable for EEE components. This document clearly identifies the requirement for maximum use and preference towards the ESA/SCC Specification System.


ESA/SCC DOCUMENT REF/001

This identifies the existence and status of all documents and specifications issued on behalf of the Director General of ESA.

It is regularly updated and issued to all registered users of the ESA/SCC System.

At this time, this document comprises a total of >1000 documents and specifications, including:-

Percentage of Total Documents

Level 0 Series -Object and Basic Rules 0.5%Level 1 Series -Organization, Procedures and Implementation 1.0%Level 2 Series -Basic Specifications 10.5%Level 3 Series -Generic Specifications 3.0%Level 4 Series -Detail Specifications 86%


SCC DOCUMENTARY SYSTEM

FIGURE 1 - SCC DOCUMENTARY SYSTEM

Object and Basic Rules ofthe SCC System

Level 0

Organisation ProceduresImplementation(Agreements)

Level 1

System of Specificationsfor Components

Level 2

Basic Specifications

Generic SpecificationLevel 3

Detail SpecificationsLevel 4


LEVEL 2 DOCUMENTS BASIC SPECIFICATIONS

These specifications define the basic requirements for a process, document or test method.

There is no standard table of contents owing to the wide range of topics addressed.

Employs either a 5 or 7 digit code,

i.e. either

20400 Internal Visual Inspection

2049000 Internal Visual Inspection of Integrated Circuits


BASIC SPECIFICATIONS (EXAMPLES)

TEST METHODS

22900 Total Dose Steady-State Irradiation Test Method

23800 Electrostatic Discharge Sensitivity Test Method

24800 Resistance to Solvents of Marking Materials and Finishes


BASIC SPECIFICATIONS (EXAMPLES) (CONT.)

INSPECTION METHODS

2049000 Internal Visual Inspection of Integrated Circuits

20500 External Visual Inspection

21400 Scanning Electron Microscope Inspection


BASIC SPECIFICATIONS (EXAMPLES) (CONT.)

SYSTEM REQUIREMENTS

20100 Requirements for Qualification of Standard Electronic Components for Space Application

21500 Calibration System Requirements

2263502 Evaluation Test Programme for Surface Acoustic Wave (SAW) Devices

22800 ESA/SCC Non-Conformance System

24600 Minimum Quality System Requirements


LEVEL 3 DOCUMENTS GENERIC SPECIFICATIONS

GENERIC SPECIFICATIONS:

- Generic meaning “CLOSELY RELATING TO ANY GROUP OR CLASS”.

- It defines the general Inspection, Test and Documentation requirements for a group of components.

- Employs a Four Digit Code, and may refer to a Family of components or a Sub-Family of components.

An example to illustrate its use:-

EXAMPLE

4001

40 = Family Code (Resistor Family)

01 = Sub-Family Code (Metal Film)


GENERIC SPECIFICATION CONTENTS

Defines the general requirements for a component family, including:

Qualification Approval

Capability Approval

Procurement

Lot Acceptance Testing

Delivery

Inspection & Test Schedules

Data Documentation


GENERIC SPECIFICATION

TABLE OF CONTENTS1. Introduction2. Applicable Documents3. Terms, Definitions, Abbreviations, Symbols and Units4. Requirements5. Production Control for Qualification and Capability Approval6. Final Production Tests7. Burn-in and Electrical Measurements8. Qualification Approval, Capability Approval and Lot Acceptance Tests9. Test Methods and Procedures10. Data Documentation11. Delivery12. Packaging and Despatch

-- Test Flows --

-- Sampling Plans --


GENERIC SPECIFICATIONS (EXAMPLES) (CONT.)

3009 Capacitors, fixed, chips, ceramic dielectric types I and II

4001 Resistors, fixed film

5000 Discrete Semiconductor Components

9000 Integrated Circuits, Monolithics.


LEVEL 4 DOCUMENTS DETAIL SPECIFICATIONS

Defines the detail requirements for a component type, including:-• Ratings• Physical and Electrical Characteristics• Test and Inspection Data

TABLE OF CONTENTS

1. General

2. Applicable Documents

3. Terms, Definitions, Abbreviations, Symbols and Units

4. Requirements

5. Tables

6. Figures

7. Appendices


DETAILED SPECIFICATION EXAMPLES

3009/004 Capacitors, fixed, chips, ceramic dielectric type I.

4001/011 Resistors, fixed film, Non hermetically sealed.

5000/005 Diodes, silicon, fast recovery, avalanche rectifiers, 400W.

9000/001 Monolithic microwave integrated circuits (MMIC), GaAs, Travelling wave amplifier.


COMPONENT NUMBERING - RADIATION IDENTIFICATION


RADIATION IDENTIFICATION


OTHER PROCUREMENT SYSTEMS

• CECC

• NASA

• US MILITARY


CECC

The Cenelec Electronic Components Committee (CECC) System for electronic components of assessed quality became operational in 1973.

Its object is to facilitate trade by the harmonization of specifications and quality assessment procedures for electronic components.

Components produced under CECC requirements carry a special mark and are accepted by all member states.

15 countries participate in the CECC System:-

Austria, Denmark, France, Belgium, Finland, Germany, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.


CECC LOGO


CECC (Cont.)

There are a number of different types of approval available within CECC.

Manufacturers, specialist contractors, distributors and independent test houses, can each be approved for their particular capability.

Each approval carries its own award of a certificate.


CECC

Qualification Approval, CECC 00 114:part II

Enhanced Assessment of Quality, CECC 00 114:part IV

Capability Approval, CECC 00 114:part III

Technology Approval, CECC 00 114:part VI Process Approval, CECC 00 114:part V

Distributor Approval, CECC 00 114:part 1

Test Laboratory Approval, CECC 00 114:part 1


NASA

The National Aeronautics and Space Administration, NASA, was formerly established in 1958, to plan and execute the US civil space programme. It comprises about a dozen major facilities, employing around 25,000 civil servants.


MAIN NASA SITES

Goddard Space Flight Centre (GSFC)

Jet Propulsion Laboratory (JPL)

Kennedy Space Centre (KSC)

Marshall Space Flight Centre (MSFC)


NHB 5300.4

NASA programmes are controlled through a top level handbook, NHB 5300.4

This document is imposed on all contractors.

It details the requirements for the control, selection, procurement, testing and application of all flight and mission essential EEE components.

The hand book is divided into two major sections, Programme Management and Component Requirements.


NHB 5300.4 (Cont.)

The Programme Management Section also identifies the requirements to provide data to NASA in electronic form.

The Component Requirements Section addresses the detailed topics directly related to components including, selection and specification, screening, parts lists, critical parts, derating, GIDEP, traceability, handling, packaging and storage, qualification and quality conformance tests, receiving inspection and manufacturer surveillance.


GSFC PREFERRED PARTS LIST

There are numerous PPLs used within the US space industry, however the GSFC PPL is considered as one of the best.

It contains a list of preferred parts in two quality levels: Grade 1 for higher quality/critical applications and Grade 2 for less demanding applications.


US MILITARY STANDARDS

In the 1950s the US government, in conjunction with the American armed forces, introduced a series of documents to standardize the screening flows for electrical and electromechanical components. The system has continued to evolve, and now includes electronic components. The objectives being:

Total product Interchangeability

Configuration control

Efficiency of volume production

Maximum number of approved sources

These aims have in the most part been achieved


MIL-STD-883

In the early 1960s the rapidly growing Integrated Circuit industry was coming of age. It was recognised that the level of defects attributable to Infant Mortality could be significantly reduced if a standardized screening flow were introduced. The Solid State Applications Branch of the Air Forces, Rome Air Defence Center (RADC) was given the task.


MIL-STD-883 OBJECTIVE

To create an economically feasible, standardized IC screening flow, to achieve equipment failure rates of :-

0.085% per 1000hrs., class B (Military)

0.004% per 1000hrs., class S (Space)


883 ORIGINAL SCREENING FLOWS

Originally there were three screening flow classes, A,B and C:-

Class A, critical non-repairable applications

Class B, high reliability, maintainable

Class C, non-critical ground applications

Class A, was superseded by Class S in 1977

Class C, was dropped in 1984, lack of use.


883 DETAILED SPECIFICATIONS

MIL-STD-883 is a collection of test methods designed to look at specific reliability and quality concerns affecting semiconductor products.

The specification covers Environmental, Mechanical and Electrical test methods.

In addition 883 also covers a range of procedures.


883 SCREENING REQUIREMENTS

SCREENClass S Class B

Method Reqmt Method Reqmt

1. Wafer Lot Acceptance 5007 All Lots _______

2. Non-destructive Bond Pull (Note 14)

2023 100% _______

3. Internal Visual (Note 1) 2010, Condition A 100% 2010, Condition B 100%

4. Stabilisation Bake (Note 16)

1008, Condition C, Min24 hrs. Min.

100% 1008, Condition Cmin, 24 hrs. Min.

100%

5. Temp. Cycling (Note 2) 1010, Condition C 100% 1010 Condition C 100%

6. Constant Acceleration 2001, Condition E (Min)Y1 Orientation Only

100% 2001, Condition E(Min) Y1 OrientationOnly

100%

7. Visual Inspection (Note 3) 100% 100%

8. Particle Impact Noise Detection (PIND)

2010, Condition A (Note4)

100% _______

9. Serialisation Note 5 100% -------

10. Interim (Per Burn-In) Electrical Parameters

Per applicable DeviceSpecification (Note 13)

100% Per applicableDevice Specification(Note 6)

_______

11. Burn-in Test 1015240 hrs @ 125oCMin (Cond F notallowed)

100% 1015160 hrs @ 125oCMin

100%

12. Interim (Post-Burn-In) Electrical

Per ApplicableDevice Specification(Note 13)

100%

13. Reverse Bias Burn-In (Note 7)

1015; Test ConditionA,C,72 ins. @ 150oCMin. (Cond F notallowed)

100%

14. Interim (Post-Burn-In) Electrical

Per Applicable DeviceSpecification (Note 13)

100% Per ApplicableDeviceSpecification

100%

15. PDA Calculation 5% Parametric (Note14)3% Functional

All lots 5% Parametric(Note 14)

All lots


883 SCREENING REQUIREMENTS (CONTD)

SCREENClass S Class B

Method Reqmt Method Reqmt

16. Final Electrical Test (Note 15) (a) Static Tests 1) 25oC (Subgroup 1)

Table 1, 5005) 2) Max and Min Rated Operating Temp (Subgroups 2,3 Table 1,5005) (b) Dynamic Tests or Functional Tests 1) 25oC (Subgroups 4 or 7) 2) Max and Min Rated Operating Temp (Subgroups 5 and 6 or 8, Table 1,5005) (c) Switching Tests 25oC (Subgroup 9 Table 1,5005)

Per applicable Device100%Specification

100%

100%

100%

100%

Per applicableDeviceSpecification

100%

100%

100%

100%

100%

17. Seal Fine, Gross 1014 100%(Note 8)

1014 100%(Note 9)

18. Radiographic (Note 10)

2012 Two Views (Note15)

100% _______ _______

19. Qualification orQuality Conformance Inspection Test SampleSelection

(Note 11) Samp. (Note 11) Samp.

20. External Visual (Note 12)

2009 100% 100%


38510 - QUALIFICATION AND QUALITY CONFORMANCE TESTING

Each of the flows requires qualification and quality conformance testing.

The quality conformance testing frequency is defined in MIL-M-38510 (JAN product) and paragraph 1.2 of 883 (non-JAN product).

Quality conformance testing is divided into 5 groups, A, B, C, D and E.

Group A : Sample electrical testingGroup B : Sample constructional testsGroup C : performed only on class B product. Sample

reliability testingGroup D : Sample package related testingGroup E : Only required where a radiation hardness

requirement identified.


MIL-STD-883 SUMMARY

883 provides a valuable tool for the Military and Space semiconductor user.

However it does not provide the specific device electrical requirements necessary to achieve standardization.

This is established by MIL-M-38510


MIL-M-38510

Concurrent with the development of MIL-STD-883, RADC developed MIL-M-38510

MIL-M-38510, establishes the procedures which a manufacturer must follow to have his products listed in the Qualified Parts List

Also published a set of performance and electrical parameters, (slash sheets)


OBTAINING QPL LISTING

A manufacturer must meet the following requirements before obtaining QPL listing

Line Certification as defined within MIL-STD 976

Device Qualification. There are two levels of QPL listing. Part II requirements are significantly less than Part I.

Part II listing was established to expedite manufacturers into the QPL.


OBTAINING QPL LISTING (Cont.)

To obtain Part II listing, all line certifications must be complete and significant electrical, design and constructional test data submitted, and approved.

Part I listing requires significant additional testing and therefore takes much longer to complete.


QUALIFICATION BY EXTENSION

There are three ways to extend device or package qualification.

• Die related testing• Die extension• Package extension

In addition it is possible to extend qualification to differing lead finishes.


PART NUMBERING AND MARKING

MIL-M-38510 devices have a unique part numbering system.

e.g. JM38510/AAABBCDE:

J = JAN prefix

M38510 = MIL-M-38510

/ = Replaced by hardness assurance letter, when

applicable


PART NUMBERING AND MARKING (Cont)

AAA = Slash sheet no.

BB = Component no. on the slash sheet

C = Screening level S or B

D = Component package type.

E = Lead finish

e.g. JM38510/10107SGC = Slash sheet 101 device 07(LM118)

Class S, in 8 pin, TO-99 package with gold finish.


MIL-I-38535

Over the past decade, standards have not been able to keep pace with the rapidly changing technologies.

MIL-M-38510, which is very successful for simpler components was not suited to complex technologies such as ASICs, gate arrays and VLSI components.

As a result the Qualified Manufacturers List (QML) approach was implemented through MIL-I-38535

The QML approach is to qualify the manufacturer, rather than his specific products.


MIL-I-38535 (Cont.)

The manufacturer adopts a Total Quality Management (TQM) approach to his business.

This applies from the initial design phase through to customer feedback.

The objective is to demonstrate, through Statistical Process Control (SPC), continuous improvement.


MIL-S-19500

To date the information related to the US-MIL System has related to ICs.

Similar reliability concerns are held with respect to other EEE components.

This section deals with discrete semiconductor devices, incl. FETs, bipolar transistors, diodes, rectifiers and thyristors.

In 1959 the United States Navy Bureau of Ships, created MIL-S-19500, which performs the same function for discrete semiconductor products, that MIL-M-38510 provides for ICs.

MIL-S-19500 was tailored to work with the JEDEC numbering system.


MIL-S-19500 (Cont.)

The JEDEC numbering system is simple in that a three or four digit number was preceded by an XN, where X is one less than the number of active element terminations on the device.

Thus a diode has two terminations, X = 1.

Transistors generally have three terminations, thus X = 2

Dual transistors were also given a 2N number, even though their 6 pins would suggest a 5N number.

Suffixes were added to provide additional information e.g. M for matched pair.


MIL-S-19500 (Cont.)

In 1963 the Navy decided that it would be better to have a separate specification for detailed test methods.

In 1964 MIL-STD-750 was published as a “how to” of test methods for MIL-S-19500.

MIL-S-19500 establishes general requirements

Detailed requirements are specified in detail specifications.

4 levels of PA requirements are specified.

JAN,JANTX,JANTXV and JANS.


MIL-S-19500 QUALIFICATION

Before any supplier can deliver any level of JAN semiconductor products, he must undergo a formal qualification cycle.

This qualification cycle is much like that already identified for MIL-M-38510.

Once qualified the manufacturer is listed in QPL-19500.

To retain QPL listing the manufacturer has to submit, each year, a summary of all of the quality conformance testing that has been completed.

If any changes are made to the QPL listed components that affect performance, quality, appearance, reliability or Interchangeability, re-qualification may be required.


MIL-S-19500 SCREENING REQUIREMENTS

ScreenMIL STD

750Method

ConditionJAN

SReqmt

JANTXV

Reqmt

JANTX

Reqmt

1. Internal Visual (Precap) Inspection

207220732074

For TransistorsFor diodes when specified

For diodes

100% 100% ____

2. High Temp Life(LTPD)

(Stabilisation Bake)

1032 24 hrs min at max ratedstorage temp

100% 100% 100%

3. Thermal Shock (temp cycling) (Note 6)

1051 No dwell is required at 25oCTest condition C, 20 cyclest(extremes) > 10 minutes

100% 100% 100%

4. Constant acceleration (not required for

double plug diodes)

2006 Y1 direction at 20,000G min(10,000G min for deviceswith power rating of > 10

watts at TC = 25oC).

100% 100% 100%

5. Particle Impact Noise detection (for all devices with an internal cavity)

2052 Condition A 100% ____ _____

6.(a) Forward instability shock test

(FIST) (Note 5) (b) Backward instability

shock test (BIST) (Note 5)

2081

2082

100%

100%

_____ _____

7. Hermetic Seal (a) Fine

(not required for double plug diodes)

(b) Gross

1071 (a) Test condition G or H1 max leak rate = 5 X 10 -8 atm cc/s for devices with internal cavity >

0.3 cc)(b) Test condition

A, C, E or F

Optional

if doneat

step 14

Optional

100% (Note8)

100% (Note8)

8. Serialisation 100% ----- -----9. Interim electrical

parametersAs specified 100%

(Readand

record)

_____ ______

10. High temp reverse bias (HTRB) (Note 7)

Burn-In (fortransistors)

Burn-In (for diodesand rectifiers)

1039

1038

48 hrs min at TA = 150oVmin and min applied voltage

as follows:Transistor-Cond A, 80% min

of rated VCB (bipolar), VGS

(FET), as applicable

Diodes (except Zeners) andrectifiers rated < 10 amps at

TC > 100oC-80% min ofrated VR-Condition A

100%

100%

100%

100%

100%

100%


MIL-S-19500 SCREENING REQUIREMENTS (Cont.)

ScreenMIL STD

750Method

ConditionJAN

SReqmt

JANTXV

Reqmt

JANTX

Reqmt

11. Interim electrical anddelta parameters

As specified butincluding all deltaparameters as a

min. Leakagecurrent shall be

measured on eachdevice before anyother test is made

100%(Read and

record deltaparameters

within 16 hrsafter removal ofapplied voltage

in HTRB)

100% (Readand record

deltaparameterswithin 24hrs after

removal ofapplied

voltage inHTRB)

100% (Readand record

deltaparameterswithin 24hrs after

removal ofapplied

voltage inHTRB)

12 Power burn-in (Note 4)Burn in (for transistors)Burn in (for diodes and

rectifiers)

Burn in (for thyristorscontrolled rectifiers)

10391038

1040

As specifiedTransistors-Cond BDiodes (includingZeners) and allrectifiers Cond B

Thryistors

100%240hrs min240hrs min

240hrs min

100%160hrsmin96hrs min

96hrs min

100%160hrsmin96hrs min

96hrs min

13. Final electrical test (a) Interim electrical

and delta parameters for

PDA. PDA when applicable is 10%

maximum

(b) Other electrical parameters

As specifiedAll parameter

measurementsmust be completedwithin 96 hrs afterremoval from burn

in condition

100%Interim

electricaland delta

parameters(Read andRecord)Group A

subgroups2 and 3

100%Interim

electricaland delta

parameters(Read andRecord)

Group Asubgroup 2

100%Interim

electricaland delta

parameters(Read andRecord)

Group Asubgroup 2

14. Hermetic seal (a) Fine (except

double plug diodes)

(b) Gross

1071 (same as 7 above)(Note 3)

100% Optional(Note 8)

Optional(Note 8)

15. Radiography 2076 (Note 3) 100% _____ ______16. External visual

examination2071 To be performed

after completemarking

100% _____ ______


MIL-STD-202

MIL-STD-202 establishes uniform methods of testing for component parts including: Capacitors, resistors, switches, relays and transformers. The standard is only intended to apply to small parts.

The test methods have been prepared to serve several purposes:-

• To give test results equivalent to those existing in actual service

• To provide a standardized, uniform approach to testing

• To provide a range of test methods, that can be applied to

components not covered by an approved military drawing


MIL-STD-202 (Cont.)

Classes of tests. The tests are divided into three classes:-

• 101 to 199, Environmental

• 201 to 299, Physical characteristics

• 301 to 399, Electrical Characteristics


MIL-STD-202 (Cont.)

Revision of test methods are indicated by a letter following the method number

Thus the first revision to test 101 is 101A, the second 101B etc.

Test sequences are not mandatory, but are provided to give guidance.


MIL-STD-202 (Cont.)

Group I (all of the samples)Visual inspectionMechanical inspectionElectrical measurementsHermetic seal test (if applicable)

Group II a (part of sample) Group II b (balance of sample)Shock Resistance to soldering heatAcceleration Terminal strengthVibration Terminal shock

Group III (all units which have passed group II tests)Moisture resistance or seal test on hermetically sealed parts.


COMPONENT MANUFACTURERS SPECIFICATIONS

Nearly all component manufacturers have their own internal standards which form the basis for any other customer specification placed upon them.

These standards cover basic electrical, mechanical and environmental characteristics.

Increasingly manufacturers are also setting standard screening and test requirements, from which they are not prepared to deviate.


COMPONENT MANUFACTURERS SPECIFICATIONS (Cont.)

SGS-THOMSON

COMMERCIAL SPACE QUALITY LEVEL

1. Screening Specification: MIL-STD-883 Class B=, rev DPind Test Condition A.

2. Electrical Specification: ESA/SCC Table II (when applicable) orSGS-Thomson Data Book.

3. Sourcing: SCC Qualified Assembly line of Rennes FactorySCC Qualified Assembly MaterialsSCC Qualified Assembly Silicon DicesSCC Qualified Assembly Generic Quality Rules

Traceability: Each Lot identified with a data code with tracking file which is permanently stored in factory. It would not containwafer tracking data but will grant that utilised wafer are from SCC qualified radhard process.

4. Radiation: Guaranteed by Design but not tested:

Heavy Ions LU and SEU: LU FreeSEU figure available

CMOS 4000B Total Dose: 100KRad54HC Total Dose: 50KRad (100Krd upon request)Bias: Worst case

Floating Output (Tri-State)Dose Rate: 25 Rad per HourTested (Idd1, Idd2: Limit 10/40A Parameters: (Vth, Delta Vth: as SCC Spec

(Rebound, functionality: as SCC Spec

5. Certificate of Conformity and RVT Reports:They are not delivered, Parts conformity to presentQuality level being granted by Marking.

6. Packages: DIL Ceramic Side Braze (SCC Qualified),

metallic Sn-Au soldered lid (Stock items)

Upon Request FLAT Ceramic Side Braze (SCC Qualified), LCC Ceramic (SCC Qualified)


ESA/SCC TEST AND INSPECTION REQUIREMENTS


ESA/SCC TEST AND INSPECTION REQUIREMENTS

This section covers the various tests and inspections which form part of the ESA/SCC Specification System for high reliability components.

In the ESA/SCC System the inspections are divided up into:

- Special In-process Controls

- Final Production Tests

- Burn-in

- Qualification Tests

- Lot Acceptance Tests


INDIVIDUAL TESTS

Test Category of Test Probable Procurer’s Inspector Involvement

SEM InspectionInternal Visual InspectionExternal Visual InspectionElectrical Screening TestsHigh Temperature Stabilisation BakeTemperature CyclingThermal Shock (in Air)Constant AccelerationParticle Impact Noise Detection (PIND)Seal TestBurn-inRadiographyPermanence of MarkingHigh Temperature StorageBond PullDie shearMechanical Shock TestVibrationThermal ShockMoisture ResistanceSolderabilityTerminal StrengthOperating Life

DestructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveNon-destructiveDestructiveDestructiveDestructive SequenceDestructive SequenceDestructive SequenceDestructive SequenceDestructive SequenceDestructive SequenceDestructive Sequence

Reviews reportPerforms testPerforms testUnlikelyUnlikelyUnlikelyUnlikelyUnlikelyWitnesses testUnlikelyUnlikelyReview reportUnlikelyUnlikelyWitnesses testWitnesses testUnlikelyUnlikelyUnlikelyUnlikelyWitnesses test and/or inspects devicesUnlikelyUnlikely


SPECIAL IN-PROCESS CONTROLS

Special tests and inspections which are carried out during manufacturing with the intention of checking specific processing steps or sub-components of the final device.

These processing steps or sub-components are ones which have:

- Been shown to be critical in producing high reliability components and

- which cannot be tested or inspected at the end of production.


WLA

A wafer lot is a set of wafers that been manufactured together and therefore are from the same diffusion, oxidation and metallisation lot.

Wafer lot acceptance (WLA) is a series of inspections carried out on samples of die from a wafer lot. The samples must be taken from particular locations within the wafer. These positions are described in ESA/SCC Basic Specification No. 21400 or

MIL-STD-883 Method 5007.6


SAMPLE SELECTION

1. Proper sample selection is an important part of the examination method.

2. Statistical techniques using random selection are not practical, because of the large sample needed.

3. Sample selection criteria are based on minimizing test sample size yet maintaining confidence in the examination.

4. The selection of wafers is based on their position in the wafer holder. Dice at specific locations on those wafers are selected to show worst case metallisation processing defects.


DIE SELECTION PLAN


DIE SAMPLE EXAMINATION

1. All four edge directions shall be examined for each type of contact window or metallisation step.

2. Viewing angles & direction shall be chosen so as to accurately assess the quality of metallisation.

3. For multi-layered-metal systems, it will be necessary to remove the layers one at a time to expose the next underlying layer for examination.


SCANNING ELECTRON MICROSCOPE


METALLISATION STEP


EXAMPLE OF INSPECTION DEFECTS


ACCEPTANCE/REJECTION CRITERIA

1. Rejection of dice shall be based on lot process orientated defects.

2. Rejection shall not be based on workmanship and other type defects such as scratches, smeared metallisation, tooling marks, etc. Such defects will be rejected at Pre-cap inspection.


WLA DOCUMENTATION

1. Photographic

- minimum of 3 SEM, 1 each for worst case metallisation, oxide step & contact window.

2. Information traceable to each Photograph

- Manufacturer’s name & address- name & address of test house or laboratory- SEM operators/inspectors identification no.- Date of SEM inspection & photograph- component part, type or reference number- SEM inspection lot number or code- area forming subject of photograph- magnification- accelerating voltage- viewing angle


FINAL PRODUCTION TESTS

The final step in the manufacture of most types of components is the final sealing of the component package. The Final Production Tests are a series of tests and inspections carried out just before and just after the components are sealed.

Purpose is to look for:

Anomalies in the production lot


INTERNAL VISUAL

Before sealing the component it should be examined optically to verify that internal materials, design and construction are in accordance with the applicable acquisition document.

In the case of integrated circuits the inspection should be performed at both high and low magnification.


INTERNAL VISUAL


INTERNAL VISUAL


BOND STRENGTH TEST

This test measures bond strengths,evaluates bond strength distributions or determines compliance with specified bond strengths required of applied acquisition documents.

The specifications include table and graphs giving the different bond strengths required for the diameter and material of the bond wires.

A record should be made of the force at which the bond wire breaks and the applicable code for the site of break.


BOND STRENGTH AND DIE SHEAR TESTER


BOND PULL TEST


BOND STRENGTH TEST


BOND STRENGTH TEST


DIE SHEAR TEST


DIE SHEAR STRENGTH

This test is used to determine the integrity of materials and procedures used to attach semiconductor die or surface mounted passive elements to package headers or other substrates.

Failure criteria is based on:

1. Measure of force applied to die.

2. Type of failure (if failure occurs)

3. Visual appearance of residual die attach.


DIE SHEAR STRENGTH


HIGH TEMPERATURE STABILISATION BAKE

Many components initially display variations in some of their electrical parameters, but these parameters become stable after a short time at high temperature.

The ESA/SCC Generic Specification No. 9000 requires devices to be stored for 48 hours at the maximum storage temperature.


TEMPERATURE CYCLING AND THERMAL SHOCK


PARTICLE IMPACT NOISE DETECTION (PIND)


PARTICLE IMPACT NOISE DETECTOR


PIND RESPONSE


RADIOGRAPHIC INSPECTION


RADIOGRAPHY

The purpose of Radiography is, to confirm the following:-

• Absence of foreign material within the package.• Correct location/mounting of internal elements.• Correctly made internal/external connections.• Proper sealing of the device.

Radiography has the following drawbacks:-

• Aluminium bond wires and silicon are almost transparent to X-Rays• Additional tests are required to determine whether foreign material

within the package is loose.• Due to unfavourable positioning of the device, a defect maybe

undetectable


FINE LEAK TESTING

1. The most widely used fine leak tests are radioactive tracer and helium leak detection methods

2. The radioactive tracer test is most sensitive but test is complex and hazardous and the equipment is very expensive

3. For the helium test the components are placed in a bombing chamber and pressurized in helium gas. The pressure and time are dependant on the volume of the package.

4. The components are then transferred to a detector which detects the outgassing helium.


TYPICAL CONDITIONS FOR FINE LEAK TEST


BOMBING CHAMBER


FINE LEAK TESTING


GROSS LEAK TESTING

1. If the component needs to be preconditioned then it is placed in D80 perfluorinated fluid and placed in the bombing chamber under pressure for a specified amount of time.

2. The component is then immersed in D02 perfluorinated fluid at 125°C. A stream of bubbles is looked for.

3. Another gross leak test that is used in some circumstances i.e. for glass diodes is the dye penetrant test.

Here the component is placed in a dye penetrant fluid in the bombing chamber. After removal and cleaning it is inspected with ultraviolet light. Areas where the dye has entered inside cavities are easily located.


TYPICAL CONDITIONS FOR THE GROSS LEAK TEST


GROSS LEAK TEST


EXTERNAL VISUAL INSPECTION

A low magnification inspection of the external surfaces of parts.

PURPOSE: “To check the external component materials, construction and workmanship for compliance to ESA/SCC”.

Requirements taken from ESA/SCC Basic Specification series 20500.

Performed after stress tests and as a final inspection prior to delivery. Generally the final inspection activity.

Can be performed on an AQL basis of 1% in final production tests. At other times, e.g. screening, it is performed on 100% basis. Although dimensional check is generally applied on AQL of 1%.


EXTERNAL VISUAL PHOTOGRAPHS


EXTERNAL VISUAL INSPECTION SHALL INCLUDE THE FOLLOWING EXAMINATIONS

1. Marking

2. Metal Surface

3. Case

4. Feed-throughs

5. Brazed joints

6. Leads


EXTERNAL VISUAL INSPECTION REQUIREMENTS

Ensure Material and External construction are in accordance with detail specification.

External surfaces should be clean.

No corrosion.

No peeling of finishes.

No holes or cracks.

No colour change.

Except for :Tinned surfaces which may show some discolouration after endurance or high temperature storage.

:Even discolouration of body after high temperature storage.


EXTERNAL VISUAL INSPECTION REQUIREMENTS (CONT.)

Dimensional check - In accordance with the detail specification.

Marking - Legibility and permanence.

Soldered/Braised Joints - Reject if:

Solder surface not clean and smooth.

Evidence of cracks or voids.

Incomplete solder flow or coverage.

Balling of solder.

Foreign matter in solder.


DIMENSION CHECK


ELECTRICAL SCREENING TEST AND

BURN-IN


ELECTRICAL SCREENING TESTS

Electrical measurements carried out to confirm that the components do meet the electrical requirements specified for them and to remove from the lot any which do not.

It is a check for any electrical degradation which has occurred in components as a result of any stress tests. The tests can be a full set of parameter measurements at room temperature, or at high and low temperature or just a measurement of certain critical parameters to look for changes.

The details of which measurements must be carried out at any point and what results are acceptable are given in the detail specification for each component type.


BURN-IN

The purposes of Burn-in are two fold:

- Removal of infant mortalities

- To check the PDA


HIGH TEMPERATURE REVERSE BIAS

HTRB is designed to check the ability of a device to continuously block a voltage under conditions accelerated by both elevated temperatures and high voltages.

The HTRB is particularly useful when screening defective MOS devices. The primary failure modes for this stress are the leakage currents Idss and Igss.


QUALIFICATION AND LOT ACCEPTANCE TESTS


LOT ACCEPTANCE TESTS

Full ESA qualified parts undergo Lot Acceptance Testing (LAT) on samples from the production lot. This yields greater reliability assurance with respect to environmental, mechanical assembly and endurance of the devices. Within the ESA/SCC system the Lot Acceptance Tests are specified in Chart V of the appropriate Generic Specification and indicate which tests are performed, how many parts are required for each test and how many failures are permitted for each of the tests.


CONSTANT ACCELERATION


HIGH TEMPERATURE STORAGE

The test is performed by placing the components in a high temperature chamber for the specified time at a specified temperature.

Its purpose is to determine whether the components are degraded by a period of time at their maximum rated storage temperature.

After completion of the storage test, any degradation of the components is detected by using appropriate end point measurements such as leak testing, electrical testing and visual inspection.


MECHANICAL SHOCK TEST

The components are mounted on a shock machine and subjected to a series of mechanical shocks.

The purpose of this test is to check the mechanical integrity of the package, particularly the die mounting, wire bonding and package sealing.


VIBRATION TEST


VIBRATION TEST


THERMAL SHOCK

Components are alternately immersed in liquids at high temperature and at low temperature.

The number of cycles, the immersion and transfer times, the liquids to be used and the temperatures to be used are given in the appropriate specifications.

The purpose of the test is to subject the components to severe thermal stressing to reveal any mechanical weaknesses.

Any degradation caused by this test is usually detected by subsequent end point measurements such as leak testing, electrical measurements or external visual inspection.


MOISTURE RESISTANCE

Components are subjected to a number of cycles of combined high temperature and humidity.

Purpose of the test:

- Corrosion

- Moisture ingress.


OPERATING LIFE

The components are electrically stressed while simultaneously subjected to a high temperature.

→ accelerated ageing

→ simulating the normal operating life in a matter of weeks.

Arrhenius Equation: R=Ae -Eα/kT

Electrical measurements, leak testing, visual inspection performed at the end of the test to establish whether there is any degradation.


MARKING PERMANENCY TEST


PERMANENCE OF MARKING - 1


PERMANENCE OF MARKING - 2


SOLDERABILITY

This test method is to evaluate the The ability of the terminations to be:

1. Wetted by a coating of solder.

2. To produce a suitable solder fillet.

The termination is dipped in flux and allowed to dry for a few seconds, then dipped in a solder pot which is at the specified temperature for 7 - 10 secs. The termination is then cleaned in IPA and examined at a magnification of 10-15x.


SOLDERABILITY

Acceptance criteria:

1. At least 95% covered with a continuous new solder coating.

2. Pinholes, voids, porosity, nonwetting, or dewetting must not exceed 5% of the total area.


SOLDERABILITY


SOLDERABILITY


LEAD INTEGRITY

There are various tests for determining the integrity of device leads, welds and seals.

1. Straight tensile loading.

2. Application of bending stresses.

3. Application of torque or twisting stresses.

4.Application of peel and tensile stresses

The individual test conditions need to be specified.


LEAD INTEGRITY

Failure criteria:

The components should be examined at a magnification of 10 – 20x after the removal of stress any evidence of:

1. Breakage

2. Loosening

3. Relative motion between lead and body

4. Adhesion failure of solder pads

shall be considered a failure.


LEAD INTEGRITY


MICROSECTION

Components are microsectioned after potting in a suitable epoxy resin so that a microscopic examination can be undertaken for the purpose of accurately locating, identifying and characterising all the internal structural features of the samples in order to judge any defects against the criteria of the specification.

Typical components that require microsection are:

Diodes

Capacitors

Relays

Isolators

Fuses


MICROSECTION OF A CAPACITOR


ESA/SCC → ESCC

Following a SCAHC recommendation produced after consultation with the space industry, ESCC Specifications are being phased in to replace the ESA/SCC specifications.

The ESA/SCC Generic Specifications contain five charts which are:-

Chart I Testing LevelsChart II Final Production TestsChart III Burn-in and Electrical MeasurementsChart IV Qualification TestsChart V Lot Acceptance Tests

In ESCC Generic specifications, these will be replaced by:-

Chart F1 General Flow ChartChart F2 Screening Tests Chart Chart F3 Qualification and Periodic Tests


A TYPICAL COMPONENT PROCUREMENT PROGRAMME


PROCUREMENT SYSTEM SELECTION

Generally, on Larger programmes, the prime contractor selects the method by which the EEE components will be procured. The basis for the selection will depend upon the programme cost, meeting the agreed schedule, and compliance to the technical requirements.

Procurement possibilities are usually assessed under three separate headings:

- Self Procurement- Co-ordinated Procurement- Centralised Procurement


SELF PROCUREMENT

Overall higher costs:

No cost sharing between contractors

MOQs

More man power required


COORDINATED PROCUREMENT

Minimum:

Loose association of users combining procurements

Maximum:

Almost Centralised were all parts are procured through the same system to the same specifications.

Control is in theory maintained by the prime contractor who would receive schedules, specifications, non-conformances evaluation reports and other technical input from users.


CENTRALISED PROCUREMENT

All EEE component requirements are delivered to the Prime contractors managements team who then consolidate the requirements into a project procurement allocation list, which once reviewed and approved by the Procurement Management is passed to the Procurement agent to carry out the actual procurement.

If properly managed Centralised procurement offers:

- All the advantages of minimal cost

- Maximised control and uniform quality


COMPARISON OF THE COORDINATED AND CENTRALISED APPROACHES


PARTS PROCUREMENT COSTS PER SATELLITE MODEL


LEAD TIMES IN PROCUREMENT

Device Type Procurement Lead Time

Capacitor 24 – 26 weeks

Connector 24 weeks

Diode 24 weeks

IC Stock to 26 weeks

Relay 32 weeks

Resistor Stock to 12 weeks

Transistor 24 weeks


PROCUREMENT PHASES

PRE-PROCUREMENT: Those activities necessary to be completed before purchase orders can be placed upon the component manufacturers.

PROCUREMENT: The actual manufacture, test and inspections necessary to meet the purchase order requirements.

POST PROCUREMENT: Those activities required to provide confidence that the requirements have been met and to prepare the components for installation.


TYPICAL PROCUREMENT PHASES

PRE-PROCUREMENT PHASE SELECTED PARTS EVALUATION PROGRAMMES INTEGRATE SPECIFICATIONS OBTAIN QUOTATION

PROCUREMENT PHASE

PLACE ORDERS TEST AND SCREEN PACKAGE AND SHIP

MANUFACTURE PARTS QUALIFICATION OR LAT

POST PROCUREMENT PHASE RECEIVING INSPECTION AND TEST DESTRUCTIVE PHYSICAL ANALYSIS KIT MARSHAL

6 12 18 24 30MONTHS


PRE-PROCUREMENT PHASE

The objective of this phase is to complete those activities necessary to confidently place purchase orders for EEE components.

Often this phase is not properly carried out, leading to severe problems and project delays later in the programme. Those areas most commonly neglected are:-• Risk Management• Component Selection• Component Type Reduction.• Evaluation.• Obsolescence Management• Specification preparation, integration and modification.


PRE-PROCUREMENT PHASE (CONT.)

PPL

INFORM USERS

USERS DRAFT PARTS LIST

FULLY QUALIFIEDPARTS

PARTIAL ORNON-QUALIFIED

PART TYPE REDUCTIONPOSSIBLE?

NO YES

EVALUATION REQUIRED

INTEGRATESPECS

IDENTIFYADDITIONAL QUAL.

TESTING REQUIREDNO YES

REPLACE WITHQUALIFIED PART

OBTAIN QUOTES SELECT MANUFACTURER(S)& AUDIT

ACCEPTABLE UNACCEPTABLE USER MUST REPLACE

ORDER

CONSTRUCTIONAL ANALYSIS ANDANY FURTHER EVALUATION TESTS

FAIL REJECT

IDENTIFYQUALIFICATION TEST

REQUIREMENTSPASS

PREPARE SPECIFICATION AGREEWITH USERS/CUSTOMER


COMPONENT SELECTION

The equipment design engineers are responsible for the selection of EEE components. However it is the task of the component engineers to provide support and assistance in the activity, particularly with respect to standardization, quality and reliability issues.

The main tool provided to assist in the selection process is the Preferred Parts List (PPL).


THE EUROPEAN PREFERRED PARTS LIST

ECSS-Q-60-01 provides the rules for establishing the list of preferred and suitable components to be used by European manufacturers of spacecraft hardware and associated equipment.

A copy of the ECSS-Q-60-01 can be down loaded from the ECSS home page (http://www.ecss.nl/)

The EPPL can be found on the ESCIES website.

http://www.ecss.nl/


EPPL (CONT.)


EPPL (CONT.)


EPPL (CONT.)


EPPL (CONT.)


EPPL (CONT.)


PPL (CONT.)

Contractual enforcement of the PPL has sometimes been achieved, however this places a major responsibility upon the PPL developer to ensure that the components in the PPL are:-

• Capable of satisfying a wide range of design applications

• Mature in the chosen technologies to be suitable for flight

applications

• Considered to have a significant utilization

• Have an acceptable test or usage history

• Available from approved manufacturers


PPL (CONT.)

In addition to the above it is also essential that the PPL also:-

• Takes into account known single user applications

• Identifies new technologies for evaluation (Part 2)

• Is maintained and regularly updated


QML


QML (CONT.)


QML (CONT.)


PARTS LIST REVIEW

Parts list should be reviewed to check:• Availability of qualified parts.• Lead times to component delivery.• Part costs and minimum order quantities (MOQ)• Part type reductions (with implicit per part cost reductions for

buying greater quantities of a given type)• Number of DPAs necessary - Does the EEE parts plan allow

limited DPA on similar part types / date codes• Radiation test requirements• LAT levels necessary• The need for any constructional analyses • Evaluation plans (life test etc.)


PLASTIC ENCAPSULATED MICROCIRCUITS

AND

CUSTOM OFF THE SHELF DEVICES


PEMs

Space projects are increasingly interested in using PEMs.

There are a number of reliability related issues with using COTS PEMs for space including:

Traceability

Lot Conformance

Screening

Change Control

Radiation Hardness

Obsolescence


SCREENING TESTS

There are a number of tests that can be performed to increase confidence in device reliability.

Some procurement agents believe that minimal screening is necessary and that over and above the usual screening requirements it is necessary to perform little more than:

Radiographic Inspection

Scanning Acoustic Microscopy (CSAM)


SCANNING ACOUSTIC MICROSCOPY


CSAM IMAGE OF DELAMINATION


LIFTED BONDS AT THE DIE SURFACE






PEMs

But…

There are other failure mechanisms and potential concerns.


Tg of PEM PLASTICS


Screening

If you need confidence approaching that which you might have from space qualified parts you’ll need to look at performing…

DPA including Tg (Sample)

1st Electrical Test (100%)

Temperature Cycling (Sample)

Radiographic (100%)

CSAM (100%)

Electrical Test (100%)

Dynamic Burn-In (100%)

Electrical Test (100%)

Dynamic Life Test (Sample)

End Point Electrical Test(100%)

HAST (Sample)

Post HAST electrical Test (Sample)

Vibration (Sample)


COST IMPACT OF UPSCREENING

NEPAG have produced a cost model to assess the relative costs of buying space grade parts with the cost of upscreening COTS.

The model does not include non-recurring engineering (NRE) charges so the model is very conservative. NRE can run to hundreds of thousands of dollars for complex microcircuits.


NEPAG COST MODEL PER LINE ITEM


RELIABILITY ASSURANCE LEVELS

NASA has traditionally categorized space level EEE parts by reliability assurance level:

Level 1 = Most reliable, intended for use in mission critical and life support applications (US MIL Class S, V or K or ESA Level B LAT2)

Level 2 = Moderate reliability for general applications (US MIL Class B,Q or H or ESA Level C)

Level 3 = Non-mission essential, higher risk applications (MIL-STD-883 Compliant)


IMPACT OF UPGRADING


RADIATION ASSURANCE

COTS parts are not designed or manufactured to meet any particular level of radiation hardness for TID or SEE.

Radiation is a very real issue with plastic devices because plastic is an insulator and may allow charge to build up.

Radiation Hardness Assurance a must be performed on every lot further adding to the overall cost.

The lack of lot homogeneity for COTS may require testing of larger samples also driving up costs.


CONCLUSION

COTS microcircuits are not a low cost alternative to inherently space level parts.


To find out more…

NEPAG Website:

http://eee.larc.nasa.gov/forum/default_2.htm

Mike Sampson’s paper to ESCCON 2002:

https://escies.org/private/esccon2002/coasscopro.html


PLASTIC DECAPSULATION


PLASTIC DECAPSULATION


TYPE REDUCTION

Type reduction is carried out to minimize the number of component types with similar functions.

Failure to carry out this activity reduces the possibility to standardize.

This, in turn, results in significant cost increases and increased delivery times.

It is the component engineers responsibility to ensure that this task is carried out thoroughly.


COMPONENT EVALUATION

ECSS-Q-60A states. If valid and acceptable qualification of a component type cannot be demonstrated, a component evaluation and approval testing programme shall be implemented.

This programme is required to cover the following elements:-

- Design and Application Assessment

- Constructional Analysis

- Manufacturer Assessment

- Evaluation Testing

Reduction or omission of any of the above steps may be approved if sufficient evidence is provided to justify the omission.


DESIGN AND APPLICATION ASSESSMENT

The objective of the Design and Application assessment is to:-

• Identify those electrical parameters essential for the intended

application

• Justify why a fully qualified component cannot be used


CONSTRUCTIONAL ANALYSIS

Typically carried out on a sample of three representative components, the Constructional Analysis is intended to demonstrate that:-

• The standard of fabrication and assembly has been fully assessed.

• All potential failure modes are identified.

• No materials or processes have been employed which might result

in premature failure of the component.


TYPICAL CONSTRUCTIONAL ANALYSIS FLOW

6 OF, SAMPLES

PHYSICAL DIMENSIONS

ELECTRICAL MEASUREMENTS

EXTERNAL VISUAL INSPECTION

HERMETICITY

MARKING AND SERIALISATION

X - RAY

DE - CAPPING

INTERNAL VISUAL INSPECTION

MICROSECTIONING

BOND STRENGTH TEST

DIE SHEAR TEST


MANUFACTURER ASSESSMENT

This assessment, carried out against the appropriate ESA/SCC checklist, includes, but is not necessarily limited to, an audit of:-

• The overall manufacturing facility, and its organization and

management.

• The manufacturers system for inspection and manufacturing

control.

• The production line used for the component.


SPECIFICATION WRITING

Maximum use should always be made of existing specifications

But, projects sometimes require devices which:

-There is no existing hi-rel specification

-Require additional testing

-Testing is excessive


SPECIFICATION WRITING

If the required parts fall outside of existing qualification limits they can be covered by extension and a cover sheet is all that is required.

Specifications are prepared around the manufacturers datasheet and sent to the manufacturer see whether the requirements are possible and to the customer for agreement on the details. This cycle of negotiation continues until full agreement is reached.

Specifications are usually written in the same format as some existing specification such as those from MIL or ESA. It is necessary to establish which type of format is most desirable to the customer.


OBTAINING SPECIFICATIONS

Most space specifications are available free of charge through the internet.

The following sites may prove useful:

ESA Specifications:

http//www.escies.org

US Military Specifications:

http://www.dscc.dla.mil/programs/milspec/default.asp

Military and others (J-STD, IEC etc.)

http://astimage.daps.dla.mil/online/new/

http://www.dscc.dla.mil/programs/milspec/default.asp


EVALUATION TESTING

Carried out after completion of the previously identified assessments, evaluation testing is intended to determine which inspection and tests are the most appropriate to provide confidence that the component when fully meeting the procurement specification requirements, will also meet the intended mission requirements.

The types of testing to be considered include:-

• Electrical stress• Mechanical stress• Environmental stress• Assembly capability testing• Radiation testing


EVALUATION REPORT

The Evaluation Report comprises:-

• Design Assessment

• Constructional Analysis

• Manufacturer Audit

• Evaluation test report


PART APPROVAL DOCUMENTS (PAD)

Once the Pre-procurement technical activities are complete, it is of great value, and mandatory for ESA programmes to summarize the technical baseline.

The Part Approval Document (PAD), provides an excellent base for this summary.


PART APPROVAL DOCUMENTS (PAD) (CONT.)


ATTRITION AND SPARES

Allowance must be made for the provision of attrition and spares, the following excerpt from a procurement plan is an example of such a policy:-

Total User Need Manufacturing Attrition

1 - 2 13 - 5 2

5 - 500 10% or 3 whichever is greater500+ 50


OBSOLESCENCE MANAGEMENT

How can we minimise the affects of obsolescence?

-At the design phase the selection of the components must have the maximum predictable life span.

-Procure sufficient components for the intended programme and any envisaged ‘follow on’ programmes

-Monitor the availability of components used in the design and allow the implementation of ‘last time buy’

-Joining obsolescence groups can yield opportunities to discuss ‘work around solutions’ with other engineers


OBSOLESCENCE MANAGEMENT (CONT.)

- There are manufacturers who specialise in buying die stock from manufacturers who are phasing out product types.

- Assembly and Test Houses can package and screen product if die is available.


RISK MANAGEMENT


RISK MANAGEMENT CONCEPT

Risk management is a four step systematic and iterative process for optimising resources in accordance with the project’s risk management policy.

Four Steps:

Step1 - Define risk management implementation requirements

Step2 - Identify and assess the risks

Step 3 - Decide and act

Step 4 - Monitor, communicate and accept risks


STEP 1 – DEFINE RISK MANAGEMENT IMPLEMENTATION REQUIREMENTS

SEVERITY CONSEQUENCE SCORING SCHEME


STEP 1 – DEFINE RISK MANAGEMENT IMPLEMENTATION REQUIREMENTS

LIKELIHOOD SCORING SCHEME


EXAMPLE OF A RISK INDEX SCHEME


STEP 2: IDENTIFY AND ASSESS RISKS

Purpose:

To identify each of the risk scenarios, to determine based on the output of step 1, the magnitude of the individual risks and finally, to rank them. Data from all project domains are used (managerial, programmatic, technical)


STEP 3: DECIDE AND ACT

Purpose:

To analyse the acceptability of risks and risk reduction options according to the risk management policy, and to determine the appropriate risk reduction strategy.

-Determine measures for reducing the risk -Determine the risk reduction success/failure criteria. -Select the best risk reduction measure


STEP 4:MONITOR, COMMUNICATE AND ACCECPT

Purpose:

To track, monitor, update, iterate and communicate risks and finally to accept the risks.

Periodic assessment of risks

Illustration of risk trend over project evolution

Implementation of new risks as they arise or become evident


EXAMPLE OF A RISK TREND


READY TO ORDER


THE PURCHASE ORDER


PERFORMANCE OF AN INSPECTION


PLANNING OF INSPECTIONS

- Ensure that the manufacturer knows that you are coming and that he is aware of the exact purpose of the of the inspection

- Check that all essential documents are available.

- If previous history files are available, check for previous problems found and how they were dealt with. It is important to be as knowledgeable as possible.


DOCUMENTARY ORDER OF PRECEDANCE

To undertake an inspection the procurers inspector should use the following documentation. Whilst undertaking an inspection it is possible that conflicts between documents could occur. In such circumstances the procurer’s inspector shall take the documentary order of precedence as indicated below:-

1.Purchase order or contract

2.Detail Specification

3.Generic Specification

4.Basic Specification

5.Other reference documents


SAMPLE INSPECTION

Within the ESA/SCC System sampling inspection is performed for certain tests.

Three approaches may be found within the system:-

• Fixed sample size• Sample size dependent upon lot size, and used to assess the

lot on an AQL • Sample size dependent on lot size and used to assess the lot

based upon an LTPD

Use of sampling methods is of limited statistical significance due to discontinuous nature of space component production.


SAMPLE INSPECTION (CONT.)

Acceptable Quality Level (AQL), example

ESA/SCC Detail specification 5101/011

Electrical measurements at high temperature

Tests to be performed on a sample basis, Inspection Level II, Table II-a, AQL = 1.0 of MIL-STD-105, minimum 10% parts to be measured.

Using MIL-STD-105 , lot size 450, inspection level II requires sample size letter H, Now, using the ‘Single Sampling Plan for Normal Inspection’ code H and AQL 1.0%, gives sample 50 accept on 1, fail on 2.


SAMPLE INSPECTION (CONT.)

Lot Tolerant Percentage Defects. (LTPD) Example.

Electrical measurements at room temp. on 450 2N6033 Transistors

ESA/SCC 5203/026 a.c. parameters sample basis LTPD 7 or less.

Using LTPD sampling plan, lot sizes greater than 200, LTPD 7 or less,

The sample size is to be a reasonable size for the lot under inspection. e.g. Sample size 32 accept on 0 defects.

Sample size 55 accept on 1 defect

Summary LTPD = 7

Sample size = 32

Acceptance no. = 0

Rejection no. = 1


INSPECTIONS SUMMARY

• Inspect strictly in accordance with the requirements

• Do not allow personal feelings, lack of time or previous history affect your judgement.

• Report your findings in reasonable detail .

• Never try to correct a discrepancy, raise a non-conformance.

• Always report the sampling plan used.

• Obtain the manufacturers representatives signature to your report.

• Never lose your temper.

• If you cause any damage, of any sort, report it immediately.


QUALIFICATION TESTING

Qualification Testing of a component must be in accordance with Chart IV of the relevant ESA/SCC Generic Specification.

The Qualifying Space Agency may accept relevant and recent valid test data as replacing part, or all, of the Chart IV test requirements.

Components subjected to the qualification testing phase are considered as having undergone destructive testing.

The disposition of the qualification test lot is the responsibility of the Qualifying Space Agency.


Mechanical + Environmental Tests

TYPICAL FINAL PRODUCTION AND BURN-IN TESTSFINAL PRODUCTION TESTS

(Ref. ESA / SCC 9000 Chart II) (For Integrated Circuits)

BURN-IN AND ELECTRICAL MEASUREMENTS

(Ref. ESA / SCC 9000 Chart II) (For Integrated Circuits)

Productions and Controls in accordance with Section 5 of the Generic Specification

Special In-Process Tests

Final Assembly, Encapsulation

Stabilisation Bake

Seal Test (optional)

Electrical Measurement at Room Temperature

Electrical Measurement at High and Low Temperature (optional)

Marking (plus serialisation for Level B)

External Visual Inspection Sampling Level II - A.Q.L. 1%)

Dimension Check

Internal Visual Inspection

Parameter Drift Values (Initial Measurements)

Power Burn-in

Parameter Drift Values (Final Measurements)

Electrical Measurement at High and Low Temperature

Electrical Measurement at Room Temperature

Radiographic Inspection

Seal Test (Fine and Gross Leak)

External Visual Inspection

Check for Lot Failure (P.D.A.)

To Figure 9


TYPICAL GENERIC SPECIFICATION QUALIFICATION TEST

100 Components

Environmental / Mechanical Subgroups nnn

Assembly / Capability Subgroups

Endurance Subgroup nnnnnnnnnnninnn

15 Components15 Components15 Components 15 Components15 Components

Shock Test

Vibration nnnnnnnnnnn

Constant Acceleration

Seal Test

Electrical Measurements at Room Temperature


Temperature Cycling

Thermal Shock nnnnn

Moisture Resistance

Seal Test

Electrical Measurements at Room Temperature


Solderabilty

Permanence of Marking

Terminal Strength


Internal Visual Inspection

Bond Strength (1)

Die Shear (1)

Operating Life

Electrical Measurements during Endurance Testing

Seal Test


High Temperature Storage

Electrical Measurements during Endurance Testing

Seal Test nnn


2 1112

12

3


INCOMING INSPECTION

Once the devices arrives at the procurement agent. A Receiving Inspection Record (RIR) is produced which details of the purchase order, manufacturer, the procurement specification , lot numbers, date codes etc.

The RIR also records:

Package inspection

Parts Inspection

Data Review

DPA Allocation

Comments, observations, NCRs etc are recorded on the RIR


DATA REVIEW


DPA

The objective of DPA is to provide an engineering evaluation of a device lot to determine compliance with specified constructional requirements, evaluate processes, workmanship and the material consistency of the product.

The sample size is not statistically relevant but is intended to be a snapshot of the quality of the lot.

A typical sample size is 3 randomly selected pieces but it can be dependant on factors such as cost, quantity of lot and customer requirements.


DPA DATA RECORDS

Each DPA should be assigned a unique number for identification purposes and each component serialized if it has not been already.

DPA data records should include:

1. Outline of the DPA procedure.

2. DPA summary sheet.

3. DPA check list.

4. DPA data sheets.

5. Original X-rays and photographs

6. Other data or analysis results which support findings


COMPONENT TYPES FOR DPA

DPA is required to be performed on samples from each delivered date code of the types listed below:

Discrete semiconductorsIntegrated circuits

FiltersVariable capacitors/resistors

Ceramic capacitorsTantalum capacitorsRelays and switches

CrystalsHybrids

High voltage componentsHigh frequency componentsOpto-electronic components


EXAMPLE DPA FLOW FOR AN INTEGRATED CIRCUIT

External visual MIL-STD-883 method 2009.7

Mechanical parameters Manufacturers data sheet

Fine leak MIL-STD-883 method 1014.7 cond A1

Gross leak MIL-STD-883 method 1014.7 cond C

Radiographic MIL-STD-883 method 2012

PIND MIL-STD-883 method 2020

Marking permanence ESA/SCC 24800

Lead integrity MIL-STD-883 method 2004.5 cond B2

Solderability MIL-STD-883 method 2003.4

Internal visual MIL-STD- 883 method 2010.8 cond A

SEM inspection MIL-STD-883 method 2018.3

Wire bond strength MIL-STD-883 method 2011.5 cond D

Die shear strength MIL-STD-883 method 2019.5


EXAMPLE DPA FLOW FOR A DIODE

External visual MIL-STD-750 method 2071.4

Mechanical parameters MIL-PRF-19500/***

Marking permanency ESA/SCC 24800

Solderability MIL-STD-750 method 2026

Internal visual MIL-STD-750 method 2074.3

Microsection MIL-STD-750 method 2074.3


NON CONFORMANCE CONTROL

The European Space Agency has a very precise way of dealing with non conforming product and if it is an ESA project that is being worked upon then it is a requirement that the ESA/SCC approach to NCRs is followed. This is defined in ESA/SCC 22800

Many companies consider this to be too rigid and adopt a more relaxed approach.


INITIATION OF THE ESA/SCC NON-CONFORMANCE SYSTEM

There are two distinct ways of initiating the ESA/SCC Non-Conformance System:-

• The Chief Inspector of the ESA/SCC qualified manufacturers,

• The user of the ESA/SCC Specification System,

The former is not only required to initiate the Non-Conformance System but also to take responsibility for the initiation of the system for any non-conformance brought to their attention from any source.

The latter also have a major responsibility toward the system, in that they are users of the ESA/SCC System.


THE MANUFACTURER'S CHIEF INSPECTOR

There are clearly defined occasions when the Manufacturer's Chief Inspector must initiate the non-conformance procedure, i.e.:-

• During final production tests.

• As a result of a PDA failure

• As a result of Qualification failure

• As a result of LAT failure.


THE ESA/SCC SYSTEM USERS

Any person in attendance at an ESA/SCC Qualified Manufacturer's premises to conduct or witness a test or inspection on ESA/SCC qualified component lots will raise a NCCS on finding the following:

• Any serious breach of quality or safety procedures.

• Clear evidence that the Process Identification Document (PID) has been modified without ESA/SCC approval.

• Evidence that the lot submitted for inspection does not originate from the master lot identified.

• Should the manufacturer refuse to accept the rejection of any defects found.


THE ESA/SCC SYSTEM USERS (Continued)

• If any data to be reviewed is incomplete, inaccurate, or results in rejection of the data.

• Once components have been delivered by the component manufacturer to the orderer, the ESA/SCC Non-Conformance System, as defined within ESA/SCC 22800, shall continue to be applied.


FLOW DIAGRAM OF NON-CONFORMANCE PROCEDURE

LEVEL DETERMINATION

LOCAL MRB Decision

Corrective Action

Distribution

NC Closed

ESA / SCC MRB Decision:

• Reject from Lot • Rework • Use”as is” (waiver)

Distribution

Corrective Actions

NCR Closed

File in Qualification Report

Initiate D.C.R. nn

D.C.R. decision by

SCCG

Review of Qualification

Status by SCCG

Reject

ESA / SCC QPL

NON-CONFORMANCE

Telex Notification to ESA / SCC

NO

YES

21

ESA / SCC Documentation Affected

Lot Rejection


NON-CONFORMANCE PROCEDURES

• All non-conformances are notified to a Materials Review Board, by means of a Non-Conformance Control Sheet.

• The Non-Conformance Control Sheet initially details the details of the non-conformance and, later, analysis of the failure, the MRB decision and confirmation that all

necessary actions have been carried to their conclusion.




NON-CONFORMANCE LEVELS

There are two levels of Non-Conformance:

LEVEL 1: MINOR - Any departure from the requirements which can be corrected and will not contravene ESA/SCC documentation.

MINOR Non-Conformances result in Local Material Review Boards (MRB).

LEVEL 2: MAJOR - All other Non-Conformances.

MAJOR Non-Conformances result in ESA/SCC Material Review Boards (MRB).


LOCAL MRB

Local MRB shall be composed, as a minimum, of the following persons:-

• Chief Inspector of the manufacturer (Chairman)

• National Space Agency representative

• Responsible engineer of the manufacturer

• Representative of the Orderer (in the case of procurement)

Members of the MRB may call in specialists as required, but they shall not have voting rights.


LOCAL MRB (CONT.)

In determining the disposition and corrective action to be taken, the

board shall:

• Take all necessary action to investigate the causes of the

non-conformance.

• Review the records of previous actions applicable to similar or identical cases.

• Consider the recommendations of specialists acting in an advisory capacity.

• Initiate failure analysis of failed items, if appropriate.

• Consider and record the effects of the non- conformance on contractual requirements.


ESA/SCC MRB

The ESA/SCC MRB shall be composed, as a minimum, of the following persons:-

• National Space Agency representative (Chairman)

• Chief Inspector of the manufacturer

• Qualification Manager of the manufacturer

• ESA/SCC Representative having acceptance authority

• Representative of the Orderer (if applicable)

Members of the ESA/SCC MRB may call in specialists as required, but these shall have no voting rights.


NCCS RESOLUTION (CONT.)

ACTIONS

• Disposition for corrective action,

• Disposition of the actual product that is the subject of the non-conformance (e.g. whether or not it can be of

further use),

• Any preventive measures taken.

Decisions of the MRB must be unanimous.


NCCS CLOSE-OUTThe last two lines on the NCCS allow for the confirmation and verification of the implementation of the MRB disposition.

The NSA Inspector and the Chief Inspector shall ensure, through actual inspection, that all actions are completed. Close-out requires that, as a minimum:-

• Corrective actions have been accomplished.

• The effectiveness of preventive actions has been proven.

• The necessary design or documentation changes have been accomplished and verified by tests if so decided by the MRB.

• Preventive actions have been taken also in respect of identical material.

• The NCCS is signed off by the Chief Inspector and the NSA Inspector to evidence the technical review and completion of all actions decided upon by the MRB.


NON-CONFORMANCE CONTROL SHEET DISTRIBUTION

Copies are to be sent members of the relevant MRB immediately the “Identification” and “Description” sections have been completed by the Chief Inspector.

In urgent cases, a fax or e-mail is recommended.

After close-out by the MRB the NSA Inspector is responsible for defining the distribution list and for its distribution.


DISTRIBUTION OF NON-CONFORMANCE CONTROL SHEET (CONT.)

For both non-conformance levels, the standard distribution list shall include as a minimum:-

• The Chief Inspector of the Manufacturer.

• The Qualification Manager of the manufacturer.

• The National Space Agency representative concerned.

• ESA/SCC (level 1, for information only).

• The National Space Agency concerned for incorporation in the qualification report (but only after “close-out”).

• the Orderer (in case of procurement).

• other persons concerned.


SPUR’S NON CONFORMANCE REPORT


NCR – SPUR’S APPROACH

1) The NCR is raised as soon as the non conformance is discovered with all the necessary details including which part of the procurement specification the non conformity applies to.

2) The report is then sent to the customer and negotiation between customer and supplier is entered into. An MRB is called if it is considered necessary.

3)The NCR is closed out once a decision is reached to whether they are to accept the components.

For the component supplier it is important that all NCRs are assigned unique numbers and kept in a log along with any written agreements between the supplier and the customer.

Copies of the NCRs must then accompany the components to the customer.


ESA ALERT SYSTEM

The ESA Alert system was launched in December 1995.

This system is aimed at providing awareness of failures and problems experienced in space projects, in order to eliminate or minimise their impacts and prevent their recurrence in current and future projects..

The ESA Alert System and its implementation procedure is fully described within Q/EAS/PROC/1

Details of how to receive ESA Alerts can also be found via the ESCIES website (www.escies.org) or go directly to: http://www.estec.esa.nl/qq/alerts

http://www.escies.org/


ESA ALERT SYSTEM


ESA ALERT SYSTEM


ESA ALERT SYSTEM


ESA ALERT SYSTEM


COMPONENT RELIFE TESTING


COMPONENT RELIFING

If a EEE component has exceeded its shelf life a relifing procedure can be used validate an extension to life.

Relifeing Procedure:

A set of tests performed in order to verify that the initial quality and reliability levels have not been affected by time.

Relifing is not usually systematically applied to shelf life components when they reach expiry date. It is initiated whenever an intended supply arises from a batch in question at a post expiry date.


RELIFING (Cont.)

The shelf life and the time that a EEE component can be used after relifing is detailed in a number of ‘Relifing Rules’ published by a number of organisations in the space industry such as:

ESA – PSS 01 60Astrium – CDSP-FD012-PRECNES – QFT-IN-0110MM-5210-02

None of these documents are backed up their figures and rules with consistent approach and physics.

Astrium under contract from CNES and ESA have updated the ESA rules taking into account field-return and failure mechanism analysis and have established a new storage and de-storage procedure that is to be included in ECSS format.


RELIFING (Cont.)

The number of samples required for relifing is usually defined in the specification and in is usually 100% or by AQL sample according to test and component type.

Specifications and methods used during relifing should be the same as those implemented at the initial procurement, except the most recent update issues should be applied.

Required test vary from between specifications and component type but typically they might be:

Electrical Parameters


Solderability

Hermeticity


TYPICAL TIME PERIOD DEFINITIONS

T1 T2 T3 T4

SAVERS 10

YEARS

10

YEARS

3

YEARS

4 MONTHS

CONNECTORS

&

ACCESSORIES 6

YEARS

10

YEARS

4

YEARS

4 MONTHS

ALL OTHER

COMPONENTS6

YEARS

9

YEARS

3

YEARS

4 MONTHS


ASTRIUM STUDY I

The CNES study consisted of two elements:

Analysing >4000 batches of relifing data from Astrium.

96% of the lots exhibited no problems.

Vast majority of failures were visual discrepancies such as corrosion on leads.

No defects resulted from a clear failure mechanism induced by storage.

A small percentage of defects remained due to random defects implying that it is still necessary to screen at the relife of parts.


ASTRIUM STUDY II

Batches of stored devices were subjected to life 3000hr life test in order to understand some potential effects of long term storage (10 years) on reliability.

Part types tested:Resistors: Metal Film and Power Wire-woundCapacitors: Ceramic and Solid TantalumTransistors: Signal and Power BipolarDiodes: ZenerIC: IREG and OP AMPRelays: Non-LatchingInductors

None of these parts exhibited any clear reliability concern.


RESULTS OF THE ASTRIUM STUDY

Astrium findings are summarised as follows:

1)No reliability issue is to be feared on relifed parts when proper storage conditions are in place.

No clear effect of storage duration was found on a relifed test yield.

2) Recommendation to allow a longer period of time before it becomes necessary to relife. This period of time is a function of the device type and storage class.

3) Relifeing tests are considered necessary to sort out the low percentage of potentially weak parts.


ASTRIUM CONCLUSION

An extended period of storage is now allowed. This will give users a better economical output keeping all reliability guarantees for these parts.


NEW SPECIFICATION

Two classes of storage defined: Class A and Class B

Class B: Based on a controlled atmosphere

Class A: Based on neutral ambience or dry air


NEW SPECIFICATION – ENVIRONMENTAL REQUIREMENTS


NEW SPECIFICATION:TIME PARAMETERS-DEFINITION AND VALUES

T0: Original date codeT1: Maximum allowed period with no relifing controlΔT: Maximum allowed storage period after relifing controlN: Maximum number of relifing authorisedT2: Absolute maximum storage duration N=1 N=2 N=…T0→→→→T1→→ΔT→→ ΔT…→

T0→→→→→→→→→→→→→→T2

Not all relife steps are necessary.A user can decide to only relife his parts just before they are used i.e. before T2 is elapsed.


TIME PARAMETERS vs. CATEGORIES.

CAT1: Generally for class A storage

CAT2: Generally for class B storage

CAT3: Case by Case

T1 ΔT N T2

Category 1 9 years 3 years 2 15 years

Category 2 6 Years 3 years 3 15 years

Category 3 Case by Case

3 years Case by Case

Case by Case and <15 years


EXTRACT FROM ASTRIUM SPECIFICATION


ELECTROSTATIC DISCHARGE (ESD)


ELECTROSTATIC DISCHARGE (ESD)

ESD is a major cause of premature failure in electronic components

Together with Electrical Overstress (EOS) it can account for over 50% of all field failures

ESD is totally preventable if proper precautions are taken


WHAT IS ESD ?

Charge is stored in insulators and is dissipated upon contact with a conductor.

Static charge build up in a typical working environment can generate potentials ranging from 100V to 20 kV build up . If this is then discharged through a semiconductor the burst of charge can cause serious damage and cause the device to fail.

Components can be damaged by contact with a charged body of by exposure to a high electric field


ELECTRICAL FIELD SURROUNDING A STATICALLY CHARGED PERSON


ESD PROTECTIVE MEASURES

- Handling and storage at RH between 45% and 55%- Grounding of devices, equipment and tools- Avoid of insulating materials that are subject to charge

accumulation (particularly plastics)- Conducting work surfaces, floors and storage cabinets- Use of containers and packing materials with ESD protection- Grounding of personnel by wrist and/or heal straps- Nylon coats must not be worn. Untreated cotton is preferred.


TYPICAL ELECTROSTATIC VOLTAGES

Means of Static Generation Electrostatic Voltages

10% to 20% Relative Humidity 65% to 90% Relative Humidity

Worker at bench 6,000 100

Vinyl envelopes for work instructions 7,000 600

Walking over Vinyl floor 12,000 250

Work chair padded with polyurethane foam 18,000 1,500

Common poly bag picked up from bench 20,000 1,200

Walking across Carpet 35,000 1,500


TYPICAL CHARGE SOURCES

Object or Process Material or Activity

Work Surfaces Waxed, painted or varnished surfacesCommon vinyl or plastics

Floors Sealed concreteWaxed, finished wood

Common vinyl tiles or sheeting

Clothes Common clean room smocksCommon synthetic personal garments

Non-conductive shoesVirgin cotton

Chairs Finished woodVinyl

Fibreglass

Packaging and Handling Common plastic - bags, wraps, envelopesCommon bubble pack, foam

Common plastic trays, plastic tote boxes, vials, parts bins

Assembly, Cleaning, Test and Repair Areas

Spray cleanersCommon plastic solder suckers

Solder irons with ungrounded tipsSolvent brushes (synthetic bristles)

Cleaning or drying by fluid or evaporationTemperature chambers

Cryogenic spraysHeat guns and blowers

Sand-blastingElectrostatic copiers


THE EFFECTS OF ESD


FAILURE ANALYSIS


FAILURE ANALYSIS

1) Background research

2) Avoid additional stresses when removing the component

3) Observe proper handling

4) Never de-lid a component until all external tests are completed.

5) De-lid with extreme care and with the most appropriate method.

6) Do not jump to conclusions

7) Report findings as soon as the analysis is complete

8) Give serious consideration to the conclusions and recommendations


EXAMPLE OF A FAILURE ANALYSIS – CHIP RESISTORS


EXAMPLE FAILURE ANALYSIS


EXAMPLE FAILURE ANALYSIS – RADIOGRAPHIC INSPECTION








CONCLUSION

The internal close-up inspection of the failing devices showed that the metallisation near the termination has become thin to the point of electrical open circuit. The most likely cause of this would appear to be Electrical Over Stress.

The point of break down occurs in the weakest area of the network of tracks, which is where current density would be at a maximum during operating conditions.

A similar inspection of the good parts shows no visible signs of defect in this (or any other) area.


INTERMETALLICS


TIN WHISKERS


WARNING!

Due to legislative pressures in recent years, the electronics industry is being pushed into eliminating lead from their products and manufacturing processes. This has resulted in many manufacturers moving towards pure tin electroplates.

But…

PURE TIN ELECTROPLATES CAN CAUSE POTENTIALLY DAMAGING GROWTHS KNOWN AS TIN WHISKERS.


WHAT ARE TIN WHISKERS?

• ‘Hair-like’ single crystal structures that may grow from tin finished surfaces.

• Length: Up to 10mm (typically <1mm)

• Diameter: from 6nm to 10μm (typically ~ 1μm)

• Growth from the base not the tip

• Whisker extrusion is driven by mechanical stress relief and diffusion processes in the tin finish.


EXAMPLES OF WHISKER GROWTH


SURFACE MOUNT CAPACITOR


TIN WHISKERS


A POSSIBLE MECHANISM FOR WHISKER GROWTH

1. Substrate elements (Cu, Zn, etc.) diffuse into tin along grain boundaries

2. Intermetallic compounds (IMC) may form preferentially in the grain boundaries

3. As a result stress builds up in the tin layer.

4. To relieve stress, whiskers extrude through ruptures in the tin oxide.


WHY SHOULD YOU BE CONCERNED ABOUT WHISKERS?

• Electrical Short Circuits - Permanent (if current < 10s of mA)

- Intermittent (if current > 10s of mA)

• Metal Vapour Arc in Vacuum - Atmospheric pressure < ~150 torr, V> ~18V and I>10s of Amps, then

whisker can vapourize into highly conductive plasma of tin ions.

- Plasma can form arcs capable of carrying HUNDREDS OF AMPS

- Arc is sustained by tin evaporated from the surrounding area

• Debris/Contamination - Interfere with sensitive optics

- Cause shorts in areas remote from whisker origins


WHAT CAN BE DONE?

Reduction of Stress• Hot oil reflow / hot solder dip (preferably Sn/Pb solder)• High temperature anneal substrate and tin finish• Underplate with diffusion resistant barrier may delay onset.

Use of Physical Barriers to Insulate against Potential Shorts• Conformal coat or other insulating barriers• Increased spacing of surfaces of opposite polarity > 0.5 inches

AVOID PURE TIN IF POSSIBLE


SOME LIMITATIONS – HOT SOLDER DIP

Hot Solder Dip does not always allow complete coverage of terminals to the component body.

There is a risk of heat damage to the component package and the seals.


SOME LIMITATIONS - CONFORMAL COATING

Conformal coating reduces (but does not eliminate) rate of whisker growth compared to an uncoated specimen.

Whiskers have grown through 0.25 mil (6μm) Uralane 5750 coating.


For Further Information…

NASA’s Goddard Space Flight Centre runs the

‘Tin Whisker Home Page’:

http://nepp.nasa.gov/whisker/