Design for the Environment Printed Wiring Board Project Presentation of the Surface Finishes Cleaner Technologies Substitutes Assessment (CTSA) Results

Design for the EnvironmentPrinted Wiring Board Project

Presentation of the Surface Finishes

Cleaner Technologies Substitutes Assessment (CTSA) Results

Presented in coordination with the Chicagoland Circuit Association

Elk Grove, IL

November 29, 2000

2

Acknowledgments

This seminar presents the results of the Surface Finishes Cleaner Technologies Substitutes Assessment (CTSA), written by Jack Geibig, Mary Swanson, and Rupy Sawhney of the University of Tennessee’s Center for Clean Products and Clean Technologies. Valuable contributions to the project were provided by the project’s Core Group members not already mentioned above, including: Kathy Hart, EPA Project Lead and Core Group Co-Chair; Holly Evans and Christopher Rhodes, formerly of IPC-Association Connecting Electronics Industries, Core Group Co-Chairs; Dipti Singh, EPA Technical Lead and Technical Workgroup Co-Chair; John Sharp, Teradyne Inc., Technical Workgroup Co-Chair; Michael Kerr, BHE Environmental Inc., Communication Workgroup Co-Chair; Gary Roper, Substrate Technologies Inc.; Greg Pitts, Microelectronics and Computer Technology Corporation; and Ted Smith, Silicon Valley Toxics Coalition.

We would like to acknowledge Ron Iman (505/856-6500) of Southwest Technology Consultants and Terry Munson of Contamination Studies Laboratory (CSL) for their work in planning and analyzing the results of the performance demonstration. Acknowledgment is also given to the suppliers of the technologies evaluated in the CTSA, including Alpha Metals; Dexter Electronic Materials; Electrochemicals, Inc.; Florida CirTech; MacDermid, Inc.; and Technic, Inc., who, in addition to supplying the various technologies, contributed significant technical input for the performance demonstration. Recognition is also given to ADI/Isola, who supplied the materials for the performance demonstration, to Network Circuits, for volunteering their services to build and test the boards, and to the sixteen test facilities.

We would also like to express appreciation to Andrea Blaschka, Susan Dillman, Conrad Flessner, Franklyn Hall, Susan Krueger, Fred Metz, and Jerry Smrchek, as members of the EPA Risk Management Workgroup, who provided valuable expertise and input during the development of the CTSA. Many thanks also to the industry representatives and other interested parties who participated in the Technical Workgroup, for their voluntary commitments to this project.

6


Partnerships for a Cleaner Future

7

DfE Vision

Business decision-makers integrate environmental concerns into cost and performance criteria

Cost Performance

Environment

Decision

8

Project History

Began working with the PWB industry in 1993

MCC study assessed the life cycle of a computer workstation Material and chemical use Hazardous waste Water use Energy use Conducted assessment of making holes

conductive technologies as first project

9

Project Partners

Partnersfor

Change

PublicInterestGroups

EPA

IPCPWB Manufacturers and Suppliers

MCC

UniversityofTennessee

10

DfE Workgroups

Technical Occupational exposure Environmental releases Performance Cost Information products

Implementation Seminars Implementation

guides Web site Community outreach

Communication P2 case studies Presentations Trade show booth Trade journals

Core

11

Information Products

Implementing Cleaner PWB Technologies: Surface Finishes PWB Cleaner Technologies Substitutes Assessment:

Making Holes Conductive Implementing Cleaner Technologies in the PWB Industry:

Making Holes Conductive PWB Pollution Prevention and Control: Analysis of Updated

Survey Results PWB Industry and Use Cluster Profile Federal Environmental Regulations Affecting the Electronics

Industry (1995) 9 Pollution Prevention Case Studies Project Fact Sheets and Journal Articles

These reports can be ordered through EPA’s Pollution Prevention Information Clearinghouse, at 202/260-1023, or viewed on the DfE website at www.epa.gov/dfe

12

EPA Goals and Objectives

Effect change in PWB industry that results in pollution prevention

Leverage industry resources Foster open and active participation in

addressing environmental issues Demonstrate that pollution prevention

makes economic sense

13


Industry Perspectives

14

Industry Goals and Objectives

Identify and implement P2 technologies that perform competitively and are cost-effective

Make informed decisions that include consideration of human health and environmental risk

Develop useful information for PWB industry within a short time frame

Help ensure credibility and validity of project data

15

Benefits to Industry

Research conducted by neutral parties

Risk assessment expertise

Full-time project leadership

Change from confrontational to partnering relationship

16

Benefits to Industry

Proactive management of environmental affairs and increased competitiveness: Reduce health and environmental risk Reduce material and compliance costs Reduce liabilities

Leverages limited resources of small to medium-sized businesses

17

Advantages of DfE Approach

Cooperative approach to environmental problem-solving

Focused project that produces useful data and facilitates pollution prevention

EPA funding, which includes: Development and analysis of data Demonstration of alternative

technologies Communication of cost-effective P2

information

18


Community Perspectives

19

Community Goals and Objectives

Encourage the development of cleaner and safer technologies that provide better protection for workers and the community

Develop a model for cleaner technology assessment, development, and implementation

Learn more about the PWB industry and disseminate that information

Help to equip community residents and workers to become more informed stakeholders so they can be more effective participants in joint projects

Ensure that the DfE process is credible to communities and workers and that it is conducted in a comprehensive, fair, and equitable manner

20

Potential Benefits to the Community and Workers

The partnership and combined expertise between government, industry, academia, and NGOs can lead to an improved process, product, and data

The results of the DfE process, if conducted properly and implemented successfully, can lead to improved public and occupational health

The DfE process exposes all participants to each other’s interests, needs, and contrasts, and helps to overcome stereotypes

21

Potential Benefits to the Community and Workers

The DfE process can help support environmental advocates within the industry

With the full support of all stakeholders, implementation can be more effective

The DfE process recognizes that there are mutual benefits in the relationship between industry, government, universities, communities, and workers to encourage a sustainable economy and corporate accountability

22


Introduction to PWB Manufacturing

and CTSA Methodology

23

CTSA ProcessUse Cluster Profile

Process identification Flow chart showing "steps"

Chemicals, materials,technologies

Commonly acceptedalternatives

High environmentalimpact areas

Description Phase

Risk and release Selected stepAlternate chemicals,materials, and processes

Use Cluster

Scoring

Cost and performance

Comparative risks

Environmental release

Resource conservation Energy impacts

Cleaner Technologies Substitutes Assessment (CTSA)

Informed decision by PWB Manufacturers

24

Cluster Selection

Evaluation showed essentially equal and medium risk

Making holes conductive was subject of first DfE/IPC project

Surface finishing process selected Technology alternatives were available

Timely

25

Use Cluster Selected

Surface Finishing Use Cluster

Circuit Design/Data Acquisition

Inner LayerImage Transfer

LaminateInner Layers

DrillHoles

Clean Holes

Make HolesConductive

Outer LayerImage Transfer

Surface Finish

FinalFabrication

OSP Hot Air Solder Leveling

Immersion Silver

Immersion Tin

Electroless Nickel/Palladium/Immersion Gold

Electroless Nickel/ Immersion Gold

26

CTSA Approach

Industry and use cluster profiles Pollution prevention survey Regulations affecting the electronics industry Workplace practices survey Performance demonstration Risk assessments Cost model and analysis Implementation guide Pollution prevention case studies

27

CTSA Methodology

WP Survey

P2 Survey

Industry Profiles

Regs

Perf Demo

Risk Assessments

28

Surface Finish Mechanisms

Electroless- metal plating process driven by oxidation-reduction reaction without the use of an external power source auto-catalytic reaction multiple layers

Immersion- metal plating driven by a chemical replacement reaction without the use of an external power source self-limiting reaction monomolecular layer

Coating- application of a protective layer to the board by physical contact of the chemistry to the board coating can be thin or thick

29

HASL Profile

Solder surface finish has been reliable standard for many years

Selection of flux is critical to performance Lack of planarity and presence of lead has

been driving development of alternatives Compatible with SMT and through-hole Operated in either conveyorized or non-

conveyorized mode

30

Electroless Nickel/Immersion Gold Profile

Thin layer of gold prevents the highly active nickel layer from oxidizing, thus protecting the solderability of the finish

Compatible with SMT, flip chip, and BGA technologies

Aluminum wire-bondable Operated in either conveyorized or non-

conveyorized mode

31

Electroless Nickel/Electroless Palladium/Immersion Gold Profile

Similar to Nickel/Gold, but with a palladium layer that lends added strength to the surface finish for component attachment


Both gold and aluminum wire-bondable Operated in either conveyorized or non-

conveyorized mode

32

OSP Profile

OSP applies a planar anti-oxidation coating to copper surface to preserve solderability benzotriazoles and imidazoles (thin) substituted benzimidazole (thick)


Operated in either conveyorized or non-conveyorized mode

33

Immersion Silver Profile

Organic inhibitor forms a hydrophobic layer on the silver surface, which protects solderability


Gold and aluminum wire-bondable Operated exclusively in horizontal,

conveyorized mode

34

Immersion Tin Profile

Immersion tin process utilizes a co-deposited organo-metallic compound prevents formation of a Sn-Cu

intermetallic layer inhibits dendritic growth


Typically operated in horizontal, conveyorized equipment

35

Typical Facility

Goal is to perform comparative, not absolute, evaluations

Data aggregated across alternatives to determine basic parameters, for example: average throughput operating days per year

Calculations were based on combination of average and high-end values from the Workplace Practices Survey

36

Typical Facility Characteristics

PWB operation occupies 45,400 square feet Facility manufactures 416,000 ssf of PWBs Surface finish processes

operates in 3,670 square foot room operates 307 days per year temperature is 75º F (average) ventilation air flow rate of 4,650 cu.ft./min.

37

Typical Facility - Types of Employees in SF Area

Line operators Laboratory technicians Maintenance workers Supervisory personnel Wastewater treatment operators Others (e.g., quality inspectors process

control specialist)

38

Typical Facility - SF Area Employee Data

Average employee duration in process area - 8 hour

Employee work days per year - 250 Operation picked as first shift only Conveyorized process exposure is much

lower than non-conveyorized

39

Surface Finish Automation

Process Configurations Evaluated in CTSA

Surface Finish Process Non-Conveyorized Conveyorized

HASL

Nickel/Gold

Nickel/Palladium/Gold

OSP

Silver

Tin

40

Typical Processes for Alternatives - ExamplesHASL Nickel/GoldSilver

Cleaner

Water Rinse x2

Flux

HP Rinse

Water Rinse

Microetch

Solder

Air Knife

Dryer

Cleaner

Water Rinse

Microetch

Water Rinse

Predip

Silver

Water Rinse

Dryer

Cleaner

Catalyst

Nickel

Water Rinse x2

Water Rinse

Water Rinse

Microetch

Acid Dip

Water Rinse

Water Rinse

Water Rinse x2

Gold

41


Cost Analysis of Surface Finish Technologies

42

Problem Framework

Sites A1

A2

AN

B1

B2

BN

G1

G2

GN

Database

A B C D E F G

AC ANC DNC GC

$/ssf $/ssf $/ssf $/ssf

Model Facilities

Generic Technologies

43

Project Tasks

Develop costs for model facilities that utilize the generic technologies

Develop cost estimates for the application of the surface finish for:

260,000 ssf of PWBs (avg. throughput for HASL processes)

60,000 ssf of PWBs (avg. throughput for non-HASL processes)

44

Cost Analysis Dimensions

AC ANC . . . . DNC . . . . GC

$/260,000 ssf

Model Facilities

A1 A2 AN. . . . G1 G2 GN. . . .

Actual Facilities

45

Cost Analysis Objectives

Fundamentally sound analysis of model facilities

Flexible system to calculate actual facility cost

Highlight environmental costs

46

Cost Analysis Goals

Use the process to estimate comparative costs for model facilities

Provide insight into costs for actual facilities

activity-based costs

sensitivity analysis

47

Hybrid Cost Formulation Framework

Surface Finish Processes

Development ofCost Categories

Development ofSimulation Model

Development ofTraditional Costs

Formulation

Developmentof the Bill of

Activities (BOA)

Cost Analysis

Sensitivity Analysis

48

Process operated at 6.8 hours per day Remaining 1.2 hours taken up by:

routine maintenance start up and shut down procedures

PWB panels are assumed to be available without delay when feeding surface finish process

Simultaneous bath changeouts are considered to occur simultaneously with regard to downtime

Process Model Key Assumptions

49

Production based on rate limiting step and overall cycle time

One rack is allowed in a bath at one time A rack consists of 84.4 ssf of PWB Labor is calculated using 1.1 employees to

reflect more labor intensive process Production system is cleared at the end of

a shift or before a bath is replaced

Non-Conveyorized Process Key Assumptions

50

Conveyorized Process Key Assumptions

Production based on average cycle time and conveyor speed

A panel consumes 18 inches of the conveyor

Process is operated by one line operator with regard to labor

Production system is cleared at the end of a shift or before a bath is replaced

51

Cost Categories

Cost Category Cost Components

Capital Cost Primary Equipment

Installation

Facility

Material Cost Chemical(s)

Utility Cost Water

Electricity

Gas

Licensing/Permit Cost Wastewater Discharge

Production Transportation of Material

Labor for Normal Production

Maintenance Cost Tank Cleanup

Bath Setup

Sampling and Testing

Filter Replacement

Total Cost

52

Simulation Model for the Conveyorized Immersion Tin Process

Generic Immersion Tin

O u t p u t

CLEANER RINSE x2 MICROETCH RINSE x2 PREDIP RINSE x1 IMMERSION TIN

RINSE x2DRYER

S CANNER

S CANNERS CANNER S CANNERS CANNER S CANNER

S CANNER

S CANNERS CANNER

0

53

Simulation Output for Non-Conveyorized Nickel/Gold Process

Chemical Bath Frequency Average Time/Replacement

(min)

Total Time(min)

Cleaner 7 116 812

Microetch 9 116 1,044

Catalyst 6 116 696

Acid Dip 4 116 464

Electroless Nickel 40 116 4,640

Immersion Gold 6 116 696

Total 72 8,352

54

Surface Finish Process Operating Times

Data based on 260k ssf PWB productionSurface Finish

Process SimulationRun Time

(days)

SimulationDowntime

(days)

OperatingTime

(days)

HASL [N] 43.7 5.7 38.0

HASL [C] 21.8 2.3 19.5

Nickel/Gold 212 18.8 193.4

Nickel/Palladium/Gold [N] 280 27.9 252.1

OSP [N] 35.2 6.2 29

OSP [C] 16.1 2.5 13.6

Silver [C] 64.2 3.4 60.8

Tin [N] 75.2 4.6 70.6

Tin [C] 107 2.5 104.5

BOA for Transportation of ChemicalsActivities Time

(min)Resources Cost

Transportation of chemicals to bath Labor Materials Forklift

$/transport

A. Paperwork and Maintenance $10.24/hr

i. Request for Chemicals 2 $0.34 $0.10 $0.00 $0.44

ii. Updating Inventory Logs 1 $0.17 $0.05 $0.00 $0.22

iii. Safety and environmental 2 $0.34 $0.10 $0.00 $0.44

B. Move forklift to chemical storage area

i. Move forklift to parking area 2 $0.34 $0.00 $0.12 $0.46

ii. Prepare forklift to move chemicals 5 $0.85 $0.25 $0.30 $1.15

iii. Move to line container storage area

2 $0.34 $0.00 $0.12 $0.46

iv. Prepare forklift to move line container

3 $0.51 $0.00 $0.18 $0.69

v. Move forklift to chemical storage area

2 $0.34 $0.00 $0.12 $0.46

BOA for Transportation of Chemicals

$0.23$0.06$0.00$0.171 v. Place line container(s) on forklift

$0.09$0.00$0.00$0.091.5 iv. Close chemical container(s)

$0.51$0.00$0.00$0.513 iii. Place appropriated chemicals in line container(s)

$0.56$0.00$0.05$0.513 ii. Utilize appropriate tools to appropriate containers

$0.22$0.00$0.05$0.171 i. Open chemical containers

D. Preparation of chemicals for transfer

$0.46$0.12$0.00$0.342 iii. Move chemical containers from staging to storage

$0.46$0.12$0.00$0.342 ii. Move chemical containers from storage to staging

$0.23$0.06$0.00$0.171 i. Move forklift to appropriate area(s)

$10.24/hr C. Locate chemicals in storage area

$/transport

ForkliftMaterialsLaborTransportation of chemicals to bath

CostResourcesTime (min)

Activities

BOA for Transportation of Chemicals

Activities Time (min)

Resources Cost

Transportation of chemicals to bath Labor Materials Forklift $/transport

E. Transport chemicals to line

i. Move forklift to line 2 $0.34 $0.00 $0.12 $0.46

ii. Unload line container(s) at line 1 $0.17 $0.00 $0.06 $0.23

Cost Composition for Non-Conveyorized Nickel/Gold Process

Tank Cleanup

X

X

Maintenance Cost to Produce 260,000 ssf

Bath Setup Sampling Filter Replacement

Number of tank cleanups

Cost/tank setup

annual number of samples

cost per sample

utilization ratio XX

Simulation Model (72)

BOA ($67)

Exposure Assessment (1260)

BOA ($3.70)

Simulation Model (0.76)

XX

$4,824 $1,580$3,530$1,087

59

Cost Summary: Non-Conveyorized Nickel/Gold Process

Cost Category Cost Component Cost ($)

Capital Costs Primary Equipment and Installation

Facility

$7,260

$2,930

Material Costs Chemical Products $108,600

Utility Costs Water

Electricity

Natural Gas

$1,180

$2,360

$0

Wastewater Costs Wastewater Discharge $2,050

Production Costs Transportation of Materials

Labor

$668

$19,100

Maintenance Costs Tank Cleanup

Bath Setup

Sampling and Testing

Filter Replacement

$4,830

$1,090

$3,530

$1,580

Total Process Cost $156,000

Cost based on 260k ssf PWB production

60

Total costs based on 260k ssf of PWB production

Surface Finish Process

Total Cost($)

Cost($/ssf)

HASL [N] $94,200 $0.36

HASL [C] $92,400 $0.35

Nickel/Gold [N] $156,000 $0.60

Nickel/Palladium/Gold [N] $399,000 $1.54

OSP [N] $28,700 $0.11

OSP [C] $26,300 $0.10

Silver [C] $73,800 $0.28

Tin [N] $46,900 $0.18

Tin [C] $64,700 $0.25

Cost Comparison of PWB Surface Finish Processes

61



Surface Finish Process

Total Cost($)

Cost($/ssf)

HASL [N] $20,000 $0.33

HASL [C] $19,800 $0.33

Nickel/Gold [N] $36,300 $0.61

Nickel/Palladium/Gold [N] $92,200 $1.54

OSP [N] $6,800 $0.11

OSP [C] $5,800 $0.10

Silver [C] $16,700 $0.28

Tin [N] $10,600 $0.18

Tin [C] $13,400 $0.22

Note: Costs are preliminary (not final)

62


-31%-$0.11$0.25Tin [C]

-50%-$0.18$0.18Tin [N]

-22%-$0.08$0.28Silver [N]

-72%-$0.26$0.10OSP [C]

-69%-$0.25$0.11OSP [N]

+327%+$1.18$1.54Nickel/Palladium/Gold [N]

+67%+$0.24$0.60Nickel/Gold [N]

-3%-$0.01$0.35HASL [C]

**$0.36HASL [N]

% Change from baseline

+/- ($/ssf)

260K ($/ssf)Process


63


Comparative Risk of

Surface Finish Technologies

64

Presentation Overview

Purpose of SF risk characterization Risk characterization methods Assumptions and Uncertainties Risk characterization results Process Safety Assessment

65

Purpose of SF Risk Characterization

Perform screening-level risk characterization to: compare risks of exposure to chemicals in

baseline and alternative SF processes identify areas of potential concern for SF

processes

Present information about variability, uncertainty, and key assumptions

66

CTSA Risk Characterization Process

RiskCharacterization

Workplace Practices

Source ReleaseAssessment

Human HealthHazards

EnvironmentalHazards

Exposure Assessment

67

Exposure Assessment

Occupational exposure to: line operators laboratory technicians others in process area

Ambient population exposure to: humans living near a facility aquatic organisms

Model facility approach 260,000 ssf production

68

Pathways for Worker Exposure

ChemicalSource

Exposure Medium

Exposure Route

Release Medium

InhalationInhalation

DermalContactDermalContact

ChemicalBath

ChemicalBath

Evaporation

Aerosol generation

Direct Contact

AirAir

AirAir

Equipment Cleaning

69

Occupational ExposureMethodology

Air concentrations based on: supplier bath chemistry data workplace practices data (bath temperature, etc.) air emission models

Dermal concentrations based on supplier bath chemistry data

Exposure time based on Workplace Practices Survey data Exposure frequency based on Workplace Practices Survey

data, supplier information, and modeled time to finish set amount of boards (260,000 ssf)

Default assumptions for inhalation rate, body weight, exposure averaging times

70

Occupational Exposure:Non-Conveyorized Processes

Baths are not enclosed Inhalation exposure to vapors from all

baths and to aerosols from air-sparged baths line operator is exposed 8 hours/day exposure to others is proportional to time

spent in process area no vapor controls on baths

Dermal exposure through line operation and bath maintenance, 8 hours/day

71

Occupational Exposure: Conveyorized Processes

Equipment is enclosed and typically vented to the outside

Inhalation exposure to workers assumed negligible

Dermal exposure through bath and filter replacement, bath sampling, and conveyor equipment cleaning

Dermal exposure contact time varies by process and by bath

72

Population Exposure

Inhalation exposure to humans living near a facility

No air pollution controls assumed Outdoor air concentrations modeled using an

EPA air dispersion model, and estimated air emission rates from process baths

73

Key Assumptions in the Exposure Assessment

Workers do not wear gloves; otherwise dermal exposure and risk would be negligible

Non-conveyorized lines are fully manual

Steady state air concentrations in process area

Form/concentration of chemicals in bath are constant over time

Air turnover rate = 1.56/hour (480 ft3/min. general ventilation rate, 18,200 ft3 room size)

74

Uncertainties in the Exposure Assessment

Similarity of model facility to any actual facility (variability among facilities)

Chemical concentrations in baths variation among products variation with time

Limitations of workplace practices data (variability in workplace practices)

Uncertainties in models and assumptions (modeling estimates vs. monitoring data)

75

Exposure Risk Descriptors

High-end : Accounts for persons at the upper end of exposure distribution (capture variability) 90% of actual values would be less

Central tendency: Average or median estimates of exposure values avoid estimates beyond true distribution

What if : Based on hypothetical conditions or limited data where the distribution is unknown does not describe how likely estimated level of

exposure might be

76

Descriptors for the SF Risk Characterization

Based on combination of average, high-end, and “what-if” values Aim was for overall high-end risk

characterization Average: body weight, breathing rate, bath

concentrations High-end: duration of worker activities What if: use of gloves, days/yr

Result is “what if” risk characterization

77

Uncertainties in theHazard Data

Effects of chemical mixtures Using short-term, high dose animal

studies to predict effects in humans Lack of measured toxicity data for some

chemicals Variability in characteristics of exposed

population (some people are more sensitive than others)

78

Risk Characterization Overview

Cancer risks to humans

Other chronic health risks (humans)

Aquatic risks

Results compared to levels of concern

79

Methods to Calculate Risk

Cancer risk expressed as probability result is upper bound lifetime excess cancer

risk weight of evidence also considered

Other chronic health risks expressed as ratio to reference value hazard quotient (better quality data), or margin of exposure qualitative (H, M, L) if no toxicity value was

available

80

Carcinogenic WOE Classifications of SF Chemicals

1Specific classification not presented to protect confidential ingredient identity.

Nickel/Gold

Nickel/palladium/gold

Urea Compound BPossible human carcinogen1

HASL

Immersion Tin

Lead

Thiourea

IARC Group B2

-possible human carcinogen

HASLLeadEPA Group B2

-probable human carcinogen

All processesSulfuric acidIARC Group I

-human carcinogen

Nickel/GoldInorganic metallic salt AHuman carcinogen or probable human carcinogen1

AlternativeChemicalClassification

81

Estimated for inhalation exposure to inorganic metallic salt A in the Nickel/gold process

Occupational inhalation risks for line operators non-conveyorized: “high end” estimate ranges from

near zero to 2 x 10-7 (1 in 5 million)

Estimated ambient population risks are low, with upper bound maximum of 1 in 50 billion

Cancer Risk Results

82

Chronic Health Risk Results

Low concerns for inhalation risks to nearby residents for all technologies

Occupational inhalation risks assumed negligible for conveyorized processes concerns for some chemicals in four non-conveyorized

processes

Occupational dermal exposure risks concerns for some chemicals in five non-

conveyorized and two conveyorized processes

83

SF Chemicals of Concern for Potential Inhalation Risks

Chemical HASL Nickel/Gold Nickel/Palladium/Gold

OSP Immersion Tin

Alkyldiol

Ethylene Glycol

Hydrochloric Acid

Hydrogen Peroxide

Nickel Sulfate

Phosphoric Acid

Propionic Acid

Process (NC, 260,000 ssf) a

a: Non-conveyorized Immersion Silver process not evaluated Line operator risk results above concern levels (noncancer health effects)

84

SF Chemicals of Concern for Potential Dermal Risks

a: No risk results were above concern levels for the Immersion Silver (conveyorized) process Line operator risk results above concern levels (noncancer health effects) Line operator and laboratory technician risk results above concern levels (noncancer health effects)C = conveyorized (horizontal) process configurationNC = non-conveyorized (vertical) process configuration

Process a (260,000 ssf)

Chemical HASL[NC]

HASL [C]

Nickel/gold/ (NC)

Nickel/ Palladium/gold (NC)

OSP[NC]

OSP [C]

Copper ion

Copper salt C

Copper sulfate pentahydrate

Ammonium hydroxide

Hydrogen peroxide

Inorganic metallic salt B

Lead

Nickel sulfate

ImmersionTin (NC)

Ammonia Compound A

Ammonium chloride

Urea Compound C

85

Aquatic Risk

Chemicals ranked for aquatic toxicity using established EPA criteria

Concern concentration (CC) = acute or chronic toxicity value divided by uncertainty factor

Inorganic metallic salt A, silver nitrate, and silver salt have lowest CC

86

Aquatic Hazard and Risk

CC compared to estimated surface water concentration (CSW ) Drag-out study used to estimate chemical loss

through rinse water and surface water concentrations (assuming no treatment)

Chemicals with CSW > CC evaluated further considering treatment efficiency

Aquatic risk expressed as a ratio of estimated surface water concentration to CC

87

Drag-Out Study

Develop a model that estimates the quantity and characteristics of drag-out

Use the model to: identify critical factors influencing drag-out quantify chemical loss and subsequent mass loading of

on-site treatment determine the effect of organic chemicals released

through drag-out on surface waters

Model was used to calculate a mass loading to the on-site treatment facility: inorganics assumed to be treated on-site to permit

levels organics were considered treated in POTW

88

Non-metal Chemicals of Concern for Aquatic Risk

ChemicalHASL (NC)

HASL (C)

OSP (NC)

OSP (C)

Immersion silver (C)

Immersion tin (NC)

Alkylaryl imidazole X X

Alkylaryl sulfonate X X

1,4-Butenediol X

Hydrogen peroxide X X X

Potassium peroxymonosulfate

X X X

Thiourea X

Estimated surface water concentration > Concern Concentration (CC) after POTW treatment

89

Comparing Risks to Concern Levels

E: Exposure estimateN or L: NOAEL or LOAELSF: Cancer slope factorCsw: Surface water concentrationRfD: Reference DoseCC: Aquatic concern concentration

Type of Risk Risk Indicator Concern Level

Cancer E x SF > 1 x 10 -6Noncancer -- RfD E / RfD > 1 Other (N or L) N or L / E < 100 for N, < 1,000 for LAquatic Csw / CC >1

90

0

5

10

15

20

25

30

35

Process configuration

No

. ch

emic

als

dermal gaps

inhalation gaps

dermal concern

inhalation concern

pot. carcinogen

aquatic concern

Risk Comparison

91

Risk Conclusions

Chemicals in seven process configurations may pose noncancer chronic health risks inhalation concerns: HASL, Nickel/gold,

Nickel/palladium/gold and OSP (all non-conveyorized) dermal exposure concerns: HASL (NC & C), Nickel gold

(NC), Nickel palladium gold (NC), OSP (NC & C), and Immersion tin (NC)

Cancer risk in Nickel gold process due to confidential ingredient (inorganic metallic salt A) less than 1 x 10-6

92

Conclusions, continued

Overall, for health risks: risks are uncertain for lead in HASL (more

monitoring data are needed) there are chemical risk results for human health

above concern levels for all processes evaluated except Immersion silver and conveyorized immersion tin

There are chemical risk results for aquatic life above concern levels for HASL, OSP, Immersion silver and Immersion tin

93

Process Safety Assessment

Used Material Safety Data Sheets for chemical products

Process Safety Concerns general OSHA requirements equipment safeguards

Chemical Safety Concerns flammable (F), combustible (C) explosive (E), fire hazard

(FH), Corrosive (CO), oxidizer (O), reactive (R), or unstable (U)

acute and chronic occupational health hazards other chemical hazards

94

Chemical Safety Concerns: Summary

0

2

4

6

8

10

12

14

16

HASL Ni/Gold Ni/Pd/Gold OSP Imm. Silver Imm. Tin

Process configuration (No. of MSDSs)

unstable

sudden rel. pres.

oxidizer

corrosive

fire hazard

explosive

flammable

95

Chemical Safety Concerns

Acute and chronic health hazards all alternatives listed both acute and chronic health

hazards and sensitizers all listed irreversible eye damage Immersion silver and OSP were the only alternatives not

containing a carcinogen

Other Chemical Hazards most have chemical decomposition hazards chemical incompatibilities include acids, alkalis,

oxidizers, metals, and reducing agents

96

Chemical Safety Concerns

Other Chemical Hazards, continued some have incompatibilities between chemical products

used on the same process line HASL, OSP, Immersion Silver, and Immersion Tin

contain chemical(s) that are considered flammable, explosive, or a fire hazard

all alternatives contain corrosive chemicals Immersion Tin was the only alternative not to contain

chemical(s) that were considered to be unstable, an oxidizer, or have a sudden release of pressure

97


Resource Conservation and Energy Impacts

98

Objective

Resource conservation relative use of natural resources (water,

chemicals, energy, etc.) during the surface finishing process (HASL vs. alternatives)

Energy conservation relative rate of energy consumption during

the application of the surface finish by HASL and the alternatives

99

Resource Conservation Data Types

Process specifications

Physical process parameters

Operating procedures

100

Water Consumption of Surface Finishing Processes

N = Non-Conveyorized, C = Conveyorized, HP = High pressure rinse

Surface Finish Process# of

RinseStages

Rinse WaterConsumed

(gal/260,000 ssf)

WaterConsumption

(gal/ssf)

HASL [N] 3+1 HP 3.22 x 10 55 1.24

HASL [C] 3+1 HP 2.58 x 10 55 0.99

Nickel/Gold [N] 8 5.37 x 10 55 2.06

Nickel/Palladium/Gold [N] 14 9.39 x 10 55 3.61

OSP [N] 3 2.01 x 10 55 0.77

OSP [C] 3 1.37 x 10 55 0.53

Silver [C] 3 1.37 x 10 55 0.53

Tin [N] 7 4.69 x 10 55 1.81

Tin [C] 5 2.29 x 10 55 0.88

101

Water Consumption of Surface Finish Technologies

Surface Finish Process Gal/ssf Change

HASL [N] 1.24 ---

HASL [C] 0.99 - 20%

Nickel/Gold [N] 2.06 + 66%

Nickel/Palladium/Gold [N] 3.61 + 191%

OSP [N] 0.77 - 38%

OSP [C] 0.53 - 57%

Silver [C] 0.53 - 57%

Tin [N] 1.81 + 46%

Tin [C] 0.88 - 29%

N = Non-Conveyorized, C = Conveyorized

102

Conclusions: Water Use

Several surface finish processes consumed less water than the baseline HASL process reduction primarily due to the reduced number

of rinse stages conveyorized processes typically use less

water than non-conveyorized

Magnitude of savings is facility-dependent examples: efficiency of previous process,

differences between alternatives, facility practices

103

Process Chemicals

Quantitative analysis of process chemicals was not possible due to the variability of: process-specific factors (e.g., bath

concentration, composition, operating parameters)

facility-specific factors (e.g., operating practices, bath replacement frequency)

104

Wastewater Treatment Chemicals

Quantity of treatment chemicals consumed is dependent on: process-specific factors (e.g., type of process,

water flow rate, volume of drag out) facility-specific factors (e.g., other mfg.

processes, volume of wastewater, type of treatment system)

Additional treatment steps or modifications may be desirable with certain finish processes (e.g., increased silver levels, thiourea, cyanide)

105

Energy Impacts

Energy consumption during process operation

Energy production environmental impacts

106

Energy-Consuming Equipment

Heat PWB panels to promote drying of residual bath chemistries remaining on the panel surfaces.

Type of Equipment Function

Conveyor System Automate the movement of panels through the process.

Panel AgitationMotor

Agitate apparatus used to gently rock panel racks back and

forth in the process baths. Not required for conveyorizedprocesses.

Fluid Pump Circulate bath fluid to facilitate uniform chemical contactwith all surfaces of the PWB panels.

Air Pump Compress air to be used by an air knife to blow residual bathchemisties or solder from the surface of the PWB. Air is alsoused to sparge select chemical baths in certain processes.

Immersion Heater Raise and control temperature of a process bath to theoptimal operating condition.

Solder Pot Heats solder and maintains the molten solder at proper operating conditions.

Gas Heater

107

Energy Usage Profiles

Process TypeConv Agit.

MotorAir

PumpFluidPump

BathHeat

SolderPot

Gas Dry

EnergyUsage

(BTU/hr)

HASL [N] * 1 2 3 1 1 1 219,800

HASL [C] 1 * 2 4 1 1 1 260,400

Nickel/Gold [N] * 1 1 3 4 * * 88,700

Nickel/Palladium/Gold [N]

* 1 1 3 6 * * 116,700

OSP [N] * 1 2 3 2 * 1 165,500

OSP [C] 1 * 2 3 2 * 1 203,100

Silver [C] 1 * * 4 2 * 1 180,200

Tin [N] * 1 * 4 2 * 1 142,700

Tin [C] 1 * * 3 2 * 1 177,100

108

Energy Consumption


Process TypeProcess

Operating Time(Hours)

Total EnergyConsumed

(BTU/260,000 ssf)

Energy UsageRate

(BTU/ssf)

HASL [N] 258 5.67 x 1077 218

HASL [C] 133 3.46 x 1077 133

Nickel/Gold [N] 1310 1.16 x 1088 447

Nickel/Palladium/Gold [N] 1710 2.00 x 1088 768

OSP [N] 197 3.26x 10 77 125

OSP [C] 93 1.89 x 1077 73

Silver [C] 414 7.46 x 1077 287

Tin [N] 480 6.48 x 1077 263

Tin [C] 710 1.36 x 1088 522

109

Comparison of Energy Consumption

Surface Finish Process BTU/ssf Change

HASL [N] 218 ---

HASL [C] 133 - 39%

Nickel/Gold [N] 447 + 105%

Nickel/Palladium/Gold [N] 768 + 252%

OSP [N] 125 - 43%

OSP [C] 73 - 66%

Silver [C] 287 + 32%

Tin [N] 263 + 21%

Tin [C] 522 + 239%


110

Pollutants Produced Through Energy Production

Health ConcernsPollutant Media of Release Environmental and Human

Carbon dioxide Air Global warming

Carbon monoxide Air Toxic organic, smog

Dissolved solids Water Dissolved solids

Hydrocarbons Air Odorant, smog

Nitrogen oxides Air Toxic inorganic, acid rain, corrosive,global warming, smog

Particulates Air Particulates

Sulfur oxides Air Toxic inorganic, acid rain, corrosive

Sulfuric acid Water Corrosive, dissolved solids

111

Conclusions: Energy Usage

HASL has the highest hourly energy consumption rate of all the finishing processes

The overall production time is the critical factor which drives the overall energy consumed

Energy consumption ranged by ~12X from the lowest to the highest energy consuming processes

112


Performance Demonstration of Surface Finish Technologies

113

Division of Responsibilities

Southwest Technology Consultants - Albuquerque

Analysis of test results and documentation

Raytheon Company - McKinney, TX

Environmental exposure and functional electrical testing of LRSTF PWA

Contamination Studies Laboratory, Inc. - Kokomo, IN

Failure Analysis

114

LRSTF Functional Printed Wiring Assembly

Features•PTH and SMT components•23 electrical responses•Circuitry

– High current low voltage (2)– High voltage low current (2)– High speed digital (2)– High frequency LPF (6)– High frequency TLC (5)– Other networks (4)– Stranded wire (2)

Features•PTH and SMT components•23 electrical responses•Circuitry

– High current low voltage (2)– High voltage low current (2)– High speed digital (2)– High frequency LPF (6)– High frequency TLC (5)– Other networks (4)– Stranded wire (2)

Design Needs Updating

ON HSD

HF

PTH

PTH

PTH

SMT

SMTSMT

SMT

PTH

HF Transmission lines

SW

LRSTF PWA is a good discriminator -- unlike single function test vehicles

115

Overview of Manufacturing Parameters

164 Test Boards

16 Finishing sites

6 Surface finishes HASL Immersion Ag OSP Ni/Au Immersion Sn Ni/Pd/Au

2 Fluxes Low-residue (LR) Water-soluble (WS)

23 Site / surface finish / flux combinations

116

MechanicalShock

MechanicalShock

Environmental Test Conditions

ThermalShock

ThermalShock

Phase 2

Pre-test all 164 PWAs

3 Weeks of 85°C / 85% RH

3 Weeks of 85°C / 85% RH

Phase 1

www.swtechcon.com

117

3 Weeks Exposure to 85°C / 85% RH

Pre-test prior to exposure Post-test after 3 weeks exposure 2 sets of chamber runs used

118

200 Cycles of Thermal Shock

-50°C to 125°C with 30 min dwell at each temp Instantaneous change in temperature Test after 200 cycles 2 sets of chamber runs used

119

Mechanical Shock Test

Mount PWA in rectangular aluminum frame Drop from 1 meter onto concrete as follows:

5 Times on each face (10 drops) 5 Times on each nonconnector edge (15 drops)

Test after drops completed

120

CCAMTF JTP Acceptance Criteria

Test results for all 23 circuits were compared to acceptance criteria in the Joint Test Protocol for the LRSTF PWA

These criteria require a comparison to Pre-test measurements for 17 of the 23 circuits

These criteria were developed for programs currently being conducted by the Circuit Card Assembly and Materials Task Force (21 organizations, 35 individuals)

www.swtechcon.com

121

Overall Summary of Success Rates

Test Time Anomalies Success Rate

Pre-test 2 99.9%

Post 85/85 17 99.5%

Post TS 113 96.9%

Post MS 527 85.4%

Total number of test measurements at each test time:22* circuits x 164 PWAs = 3608

*HF TLC RNF gave a constant response throughout

122

General Linear Modeling of Test Results

All test results were subjected to general linear modeling (GLM) to determine the statistically significant experimental parameters

The following GLM was used to analyze site and flux type:

Y = 0 + 1D1 + 2D2 + 3D3 + 4D4 + 5D5

+ 6D6 + 7D7 + 8D8 + 9D9 + 10D10 + 11D11

+ 12D12 + 13D13 + 14D14 + 15D15 + 16D16

+ 17D3D16 + 18D4D16 + 19D7D16 + 20D11D16

+ 21D14D16 + 22D15D16

Main Effects

2-Factor Interactions

123


D1 = 0 if not Site 2 = 1 if Site 2 D2 = 0 if not Site 3 = 1 if Site 3

D15 = 0 if not Site 16 = 1 if Site 16 D16 = 0 if flux is not water soluble = 1 if flux is water soluble

Base Case: all Di = 0Site 1 with LR flux

124


The following GLM was used to analyze surface finish and flux:

Y = 0 + 1D1 + 2D2 + 3D3 + 4D4 + 5D5 + 6D6

125


D1 = 0 if surface finish is not OSP = 1 if surface finish is OSPD2 = 0 if surface finish is not Immersion Sn = 1 if surface finish is Immersion SnD3 = 0 if surface finish is not Immersion Ag = 1 if surface finish is Immersion AgD4 = 0 if surface finish is not Ni/Au = 1 if surface finish is Ni/AuD5 = 0 if surface finish is not Ni/Au/Pd = 1 if surface finish is Ni/Au/PdD6 = 0 if flux is not water soluble = 1 if flux is water soluble

GLM Results Documented in Report

Base Case: all Di = 0HASL with LR flux

126

23 Surface Finish and Flux Combinations

SF Flux n (site)1 HASL LR 8 (1)2 HASL WS 8 (1) 3 HASL LR 8 (2) 4 HASL WS 8 (3)5 OSP LR 4 (4) 6 OSP WS 8 (4)7 OSP LR 8 (5) 8 OSP WS 8 (5) 9 OSP LR 8 (6) 10 Imm Sn LR 4 (7) 11 Imm Sn WS 8 (7) 12 Imm Sn LR 8 (8) 13 Imm Sn LR 8 (9) 14 Imm Sn WS 8 (10)

SF Flux n (site) 15 Imm Ag LR 8 (11) 16 Imm Ag WS 4 (11) 17 Imm Ag WS 8 (12) 18 Ni/Au LR 4 (13) 19 Ni/Au WS 8 (13) 20 Ni/Au LR 8 (14) 21 Ni/Au WS 8 (15) 22 Ni/Pd/Au LR 8 (16) 23 Ni/Pd/Au WS 4 (16)

127

Multiple Comparisons of SF and Flux

The goal of this statistical analysis is to determinewhich sets of means for surface finish and flux combinations are significantly different from oneanother. (See Iman, 1994 for details)

Note: statistical significance does not necessarilyimply practical significance

Multiple comparisons results are presented ingraphical displays

128

Fisher’s Least Significant Difference

Two sets of means are declared significantly different fromone another if their absolute difference exceeds Fisher’s least significance difference (LSD), which is defined as

jikn nnMSEtLSD

11,2/

where

is the level of significancet is the /2 quantile from a Student’s t distribution with n-k d.f.MSE is the mean square error for the modelnj and nj are the sample sizes for the means being compared

129

Illustration of a Boxplot

*

X.50X.25 X.75

Median UpperQuartile

LowerQuartile

Outlier

Illustration with 5 data points

130

Boxplots of HCLVPTH by Site Flux

2322212019181716151413121110987654321

7.5

7.4

7.3

7.2

7.1

7.0

6.9

6.8

SiteFlux

HC

LV P

TH

xplots of HCLV PTH by Site lu(means are indicated by solid circles)

Pre-TestHCLV PTH

HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd

WS WS WS WS WS WS WS WS WS WS WS

No Significant Differences

131

Boxplots of DPHCLVP by Site Flux

23

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17

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12

11

10987654321

0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

SiteFlux

DP

HC

LV P

TH

Boxplots of DPHCLV P by SiteFlux(means are indicated by solid circles)

Post 85/85HCLV PTH



Note Use of Post 85/85 - Pre-test


JTP

132

Boxplots of DPHCLVP by Site Flux

23

22

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17

16

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13

12

11

10987654321

0.5

0.0

-0.5

SiteFlux

DT

HC

LV P

TH

Boxplots of DTHCLV P by SiteFlux(means are indicated by solid circles)

Post Thermal ShockHCLV PTH




JTP

Note Use of Post TS - Pre-test

133

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12

11

10987654321

2

1

0

SiteFlux

DM

HC

LV P

TH

Boxplots of DMHCLV P by SiteFlux(means are indicated by solid circles)

Post Mechanical ShockHCLV PTH



Boxplots of Multiple Comparisons Resultsby Surface Finish and Flux Type


JTP

Note Use of Post MS - Pre-test

134

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12

11

10987654321

5.4

5.3

5.2

5.1

5.0

4.9

4.8

SiteFlux

HV

LC S

MT

Boxplots of HVLC SMT by SiteFlux(means are indicated by solid circles)

Pre-TestHVLC SMT




Significant Differences - No Practical Differences

JTP Acceptance Criterion 4A X 6A

135

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11

10987654321

5.4

5.3

5.2

5.1

5.0

4.9

4.8

SiteFlux

PH

VLC

SM

T

Boxplots of PHVLC SM by SiteFlux(means are indicated by solid circles)

Post 85/85HVLC SMT






136

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10987654321

5.5

5.4

5.3

5.2

5.1

5.0

4.9

4.8

SiteFlux

TH

VLC

SM

T

Boxplots of THVLC SM by SiteFlux(means are indicated by solid circles)

Post TSHVLC SMT






137

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11

10987654321

0.05

0.04

0.03

0.02

0.01

0.00

SiteFlux

DM

HV

LC S

MT

Boxplots of DMHVLC S by SiteFlux(means are indicated by solid circles)

Post Mechanical ShockHVLC SMT




SMT Components Came Off the Board During MS


138


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11

10987654321

15

14

13

12

11

10

SiteFlux

Pad

s

Boxplots of Pads by SiteFlux(means are indicated by solid circles)

Pre-Test10-Mil Pads



Significant Differences

JTP Acceptance Criterion > 7.7

139

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11

10987654321

14

13

12

11

10

SiteFlux

PP

ads

Boxplots of PPads by SiteFlux(means are indicated by solid circles)

Post 85/8510-Mil Pads






Note:Improvementover Pre-test

140

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11

10987654321

15

14

13

12

11

10

SiteFlux

TP

ads

Boxplots of TPads by SiteFlux(means are indicated by solid circles)

Post TS10-Mil Pads




NO Significant Differences


141

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10987654321

15

14

13

12

SiteFlux

DM

Pad

s

Boxplots of DMPads by SiteFlux(means are indicated by solid circles)

Post Mechanical Shock10-Mil Pads






142

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10987654321

14

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10

SiteFlux

PG

A A

Boxplots of PGA A by SiteFlux(means are indicated by solid circles)

Pre-TestPGA-A






143

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11

10987654321

13

12

11

10

SiteFlux

PP

GA

A

Boxplots of PPGA A by SiteFlux(means are indicated by solid circles)

Post 85/85PGA-A







144

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10987654321

15

14

13

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11

10

SiteFlux

TP

GA

A

Boxplots of TPGA A by SiteFlux(means are indicated by solid circles)

Post TSPGA-A






145

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10987654321

14

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12

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10

SiteFlux

DM

PG

A A

Boxplots of DMPGA A by SiteFlux(means are indicated by solid circles)

Post Mechanical ShockPGA-A






146


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11

10987654321

14

13

12

11

10

SiteFlux

PG

A B

Boxplots of PGA B by SiteFlux(means are indicated by solid circles)

Pre-TestPGA-B





147

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12

11

10987654321

13

12

11

10

SiteFlux

PP

GA

B

Boxplots of PPGA B by SiteFlux(means are indicated by solid circles)

Post 85/85PGA-B







148

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10987654321

15

14

13

12

11

SiteFlux

TP

GA

B

Boxplots of TPGA B by SiteFlux(means are indicated by solid circles)

Post TSPGA-B






149

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12

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10987654321

15

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11

SiteFlux

DM

PG

A B

Boxplots of DMPGA B by SiteFlux(means are indicated by solid circles)

Post Mechanical ShockPGA-B






150


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12

11

10987654321

14

13

12

11

10

9

SiteFlux

Gul

lWin

g

Boxplots of GullWing by SiteFlux(means are indicated by solid circles)

Pre-TestGull Wing





151

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12

11

10987654321

14

13

12

11

10

9

8

7

SiteFlux

PG

ullW

ing

Boxplots of PGullWin by SiteFlux(means are indicated by solid circles)

Post 85/85Gull Wing






152

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10987654321

15

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11

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9

8

SiteFlux

TG

ullW

ing

Boxplots of TGullWin by SiteFlux(means are indicated by solid circles)

Post TSGull Wing






153

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12

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10987654321

14

13

12

11

10

9

8

SiteFlux

DM

Gul

lWin

g

Boxplots of DMGullWi by SiteFlux(means are indicated by solid circles)

Post Mechanical ShockGull Wing






154


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10987654321

-0.3

-0.4

-0.5

-0.6

-0.7

-0.8

-0.9

-1.0

-1.1

-1.2

SiteFlux

HF

PT

H50

Boxplots of HF PTH50 by SiteFlux(means are indicated by solid circles)

Pre-TestHF LPF PTH 50MHz




Note:Initialmeasurementis low

155


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10987654321

0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

SiteFlux

DP

HF

PT

H50

Boxplots of DPHF PTH by SiteFlux(means are indicated by solid circles)

Post 85/85HF LPF PTH 50MHz




JTP: 5dB


Note: Initial lowmeasurementcauses subsequentdifference to be high

156



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10987654321

0.5

0.0

-0.5

SiteFlux

DT

HF

PT

H50

Boxplots of DTHF PTH by SiteFlux(means are indicated by solid circles)

Post TSHF LPF PTH 50MHz



JTP: 5dB


157

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10987654321

0

-10

-20

-30

-40

-50

-60

-70

-80

SiteFlux

DM

HF

PT

H50

Boxplots of DMHF PTH by SiteFlux(means are indicated by solid circles)

Post Mechanical ShockHF PTH 50MHz





JTP: 5dB


158



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10987654321

-42

-43

-44

-45

-46

-47

-48

-49

-50

-51

SiteFlux

HF

TL

50

Boxplots of HF TL 50 by SiteFlux(means are indicated by solid circles)

Pre-TestHF TLC 50MHz



159

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10987654321

5

4

3

2

1

0

-1

-2

-3

-4

SiteFlux

DP

HF

TL

50

Boxplots of DPHF TL by SiteFlux(means are indicated by solid circles)

Post 85/85HF TLC 50MHz





JTP: 5dB

160

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5

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3

2

1

0

-1

-2

-3

-4

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SiteFlux

DT

HF

TL

50

Boxplots of DTHF TL by SiteFlux(means are indicated by solid circles)

Post TSHF TLC 50MHz





JTP: 5dB

161

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40

30

20

10

0

SiteFlux

DM

HF

TL

50

Boxplots of DMHF TL by SiteFlux(means are indicated by solid circles)

Post Mechanical ShockHF TLC 50MHz





JTP: 5dB

162

Circuitry 85/85 Ther Shock Mech Shock

HCLV (2) 100.0% 100.0% 51.8%

HVLC (2) 99.7% 99.7% 50.0%

HSD (2) 99.7% 98.8% 99.1%

HF LPF (6) 98.7% 89.4% 82.6%

HF TLC (5) 100.0% 99.7% 99.4%

ON (4) 99.8% 100.0% 100.0%

SW (2) 100.0% 99.7% 98.5%

Totals 99.6% 96.9% 85.4%

Circuits Meeting JTP Acceptance Criteria afterEach Testing Sequence by Major Circuit Group

(17) (113) (527)

100% SMT

92.9% SMT

72.5% SMT

163

Breakout of HF LPF Anomalies at Post Thermal Shock by Surface Finish

Surface Finish Anomalies None

HASL 5 27

OSP 8 28

Immersion Sn 11 25

Immersion Ag 9 11

Ni/Au 2 26

Ni/Au/Pd 0 12

35 129

The hypothesis of theanomalies being uniformlydistributed over the surfacefinishes is rejected using achi-square test ofindependence.The p-value is 0.008.

(see Iman, 1994 for details).

(6.8)

(7.7)

(7.7)

(4.3)

(6.0)

(2.6)

164

Root of HF LPF Anomalies

Open PTH - a break in the metallization within the hole across its length

This is a PWB fabrication defect before the surface finish is applied - it not an assembly defect

The via is plated with a very thin layer of electroless Cu to provide a “seed bed” for the primary plating

Cu is then electroplated over the electroless Cu strike The final finish (Sn, Ag, etc.) is then applied Open PTH occurred in the small via holes in the HF sections -

small vias are difficult to plate

165

Root of HF LPF Anomalies

Open PTH

Defect was present at in-circuit and baseline testing Environmental exposure exaggerates this condition Could be related to the strength of the materials - Sn and Ag are

relatively weak Need to subject to failure analysis

166

CSL Failure Analysis Summary

Observed levels of bromide and weak organic acids (WOA) on all 20 assemblies are typical and therefore not detrimental from an electrochemical standpoint

Tested boards with known anomalies exhibit levels near or below CSL’s recommended guidelines, we can say with reasonable confidence that the anomalies are not the result of chloride, bromide, or WOA contamination

From an overall contamination standpoint, the five non-HASL surface finishes tested in this analysis performed as well if not better against the HASL finish

The few solder joint cracking failures were greater with the HASL finish, than with the alternative finishes. The opens occurred along the interface of the component leads on these older PTH technology boards.

www.swtechcon.com

167

Summary of Mechanical Shock Results

Tough Test!

Changes Observed HCLV PTH is 0.2V higher HCLV SMT is 2.6V higher HVLC SMT - components came off

board GW leakage 0.3 orders of magnitude

lower - still quite high HSD circuits 0.15ns faster - good

www.swtechcon.com

168


Summary of Project Results

169

Risk Conclusions

Chemicals in seven process configurations may pose noncancer chronic health risks inhalation concerns: HASL, Nickel/gold,

Nickel/palladium/gold and OSP (all non-conveyorized) dermal exposure concerns: HASL (NC & C), Nickel/gold

(NC), Nickel/palladium/gold (NC), OSP (NC & C), and Immersion tin (NC)

Cancer risk in Nickel gold process due to confidential ingredient (inorganic metallic salt A) less than 1 x 10-6

170

Risk Conclusions, continued

Overall, for for potential health risks risks are uncertain for lead in HASL there are chemical risk results for human health

above concern levels for all processes evaluated except Immersion silver and conveyorized immersion tin

There are chemical risk results for aquatic life above concern concentrations for HASL, OSP, Immersion silver and Immersion tin

171

Overall Cost comparison based on 260k ssf

Cost Comparison of PWB Surface Finish Technologies

Process 60K($/ssf)

260K($/ssf)

+/-($/ssf) from

Baseline

HASL [N] $0.37 $0.36 * *

HASL [C] $0.36 $0.35 -$0.01 - 3%

Nickel/Gold [N] $0.62 $0.60 +$0.24 + 67%

Nickel/Palladium/Gold [N] $1.54 $1.54 +$1.18 + 327%

OSP [N] $0.11 $0.11 -$0.25 - 69%

OSP [C] $0.10 $0.10 -$0.26 - 72%

Silver [N] $0.29 $0.28 -$0.08 - 22%

Tin [N] $0.19 $0.18 -$0.18 - 50%

Tin [C] $0.26 $0.25 -$0.11 -31%

%Change

172

Water Consumption of PWB Surface Finish Technologies

Surface Finish Process Gal/ssf Change

HASL [N] 1.24 ---

HASL [C] 0.99 - 20%

Nickel/Gold [N] 2.06 + 66%

Nickel/Palladium/Gold [N] 3.61 + 191%

OSP [N] 0.77 - 38%

OSP [C] 0.53 - 57%

Silver [C] 0.53 - 57%

Tin [N] 1.81 + 46%

Tin [C] 0.88 - 29%


173

Conclusions: Water Use

Several surface finish processes consumed less water than the baseline HASL process reduction primarily due to the reduced number

of rinse stages conveyorized processes typically use less

water than non-conveyorized

Magnitude of savings is facility-dependent Examples: efficiency of previous process,

differences between alternatives, facility practices

174

Energy Consumption of PWB Surface Finish Technologies


Surface Finish Process BTU/ssf Change

HASL [N] 218 ---

HASL [C] 133 - 39%

Nickel/Gold [N] 447 + 105%

Nickel/Palladium/Gold [N] 768 + 252%

OSP [N] 125 - 43%

OSP [C] 73 - 66%

Silver [C] 287 + 32%

Tin [N] 263 + 21%

Tin [C] 522 + 239%

175

Conclusions: Energy Usage

HASL has the highest hourly energy consumption rate of all the finishing processes

The overall production time is the critical factor, which drives the overall energy consumed

Energy consumption ranged by ~12X from the lowest to the highest energy consuming processes

to

to

to

to

to

to

= to

Overall

=Immersion Tin (C)

=Immersion Tin (NC)

Immersion Silver (C)

OSP (C)

OSP (NC)

=Nickel palladium gold (NC)

Nickel gold (NC)

==HASL (C)

AquaticcNonCancerbCancera

CostEnergyWaterRisk

Comparison to HASL (NC)Surface Finish

Alternative

a: Based on number of known or probable human carcinogensb: Based on number of chemicals with risk results above concern levelsc: Based on number of chemicals with estimated surface water concentrations above concern concentrations

Summary of Risk, Resource Use and Cost

= 10%

10-50% better 10-100% worse

50+% better 100%+ worse

to

177


Implementing Cleaner Technologies in the PWB Industry:

Alternative Surface Finishes

178

Overview

DfE PWB Project document, “Implementing Cleaner Technologies in the PWB Industry: Surface Finishes”

Based on telephone interviews with PWB manufacturers who use the technologies and those who have used and discontinued, and vendors

8 PWB manufacturers, 9 assemblers, 6 vendors

179

ASF Technologies

Immersion Silver Enthone

Immersion Tin Enthone Florida CirTech Inc.

180

ASF Technologies

Organic Solderability Preservative (OSP) MacDermid, Inc. Electrochemicals

Electroless Nickel/Immersion Gold Technic, Inc MacDermid, Inc.

Electroless Nickel/Electroless Palladium/ Immersion Gold MacDermid, Inc.

181

Operational Improvements

Improved coplanarity Reduced maintenance time Reduced costs Lower scrap rate Good press-fit for connections

182

Why Companies Switched

Customers’ specifications

Anticipated competitive advantage

Lead-free process

Improved worker safety

Appropriate for high-end PWBs

183

Comparisons to HASL Immersion Silver (2 PWB facilities interviewed)

Facility A uses Immersion silver on 5% of product, Facility B on 80% of product

Reduced cycle time Improved process safety - lower temperatures, less noise Same scrap rate as HASL, but more attention is required for

silver because of narrower process window Less maintenance time, but more lab analysis time Facility A gained a small contract as a result, but business

has not increased greatly because of the new finish; Facility B has gained some new business

Facility A required an XRF to measure silver thickness and auto-unloader for end of line

Installation took 2 weeks, debugging 1 week

184

Comparisons to HASL

Immersion silver - 1 assembly facility interviewed Facility C specifies Immersion silver because: Lead-Free Wire-Bondable, and works well with solders used Rework does not present any significant problems Simple process Low cost (only OSP is cheaper among ASFs) If a silver board is heated without solder, the silver

tarnishes

185

Technology Implementation Suggestions

“Arrange and chair a meeting with the chemical supplier and equipment manufacturer to ensure that all specifications are clearly defined.” Facility B - Immersion silver

“Manufacturers who are installing immersion silver should develop a relationship with the end users to determine the best specifications for the boards.” Facility A - Immersion silver

186

Comparisons to HASL Immersion tin - 3 PWB facilities interviewed

Facility F - 15% of product is Immersion tin Facility G - 5% of product is Immersion tin Facility E - 24% of product is Immersion tin All facilities installed their lines in > 1 week Cycle time and scrap similar to HASL Reduction in maintenance from HASL More lab analysis required than HASL Smaller process window than HASL, but better

control within that window Improved safety, and reduced energy

consumption

187

Comparisons to HASL Immersion tin - 3 Assembly facilities interviewed Drivers for Immersion tin were:

Flat, planar finish for fine-pitch SMT Lead-free finish Improvements in hole size tolerance Reduced costs

Facility J has switched back to HASL, due to incomplete coverage of boards

Facilities H and I are pleased and find that Immersion tin is closest to a drop-in replacement for HASL

Does require good handling practices to minimize corrosion and ionic contamination

188


“Make sure you have good quality control and testing procedures in place for this process and that you understand the thickness and coverage of the tin.” Assembler - Immersion Tin

“By monitoring and controlling time, temperature, and concentrations, anyone can produce a reliably solderable immersion tin surface finish.” PWB Facility E - Immersion Tin

“If you have to get the product wet for any reason prior to completion of any first time soldering operations, be sure not to leave it wet. Blow it off with compressed air to clear the water.” Assembler - Immersion Tin

189

Organic Solderability Preservative (OSP) - 2 PWB facilities interviewed OSP installed at request of large customers about

6 years ago for both facilities Cycle time similar to HASL, maybe a little faster Scrap is less than HASL Less maintenance than HASL Tighter operating window, but better control of

finish Improved process safety, less energy usage No effect on ability to recycle scrap boards

Comparisons to HASL

190

Organic Solderability Preservative (OSP) - 2 assembly facilities interviewed No compatibility problems with components Facility N has found that OSP can break down on

multiple passes; Facility L has found that DI water can remove OSP finish

Requires more careful handling Use different machines to do HASL and OSP

boards OSP required more heat and a more active flux

than HASL

Comparisons to HASL

191


“Don’t skimp on equipment. Some try to use old film developers, then have trouble with contamination. Most costs during operation are associated with drag-out, which is also equipment-dependent.” Electrochemicals - OSP

“As long as the temperature is maintained properly, the same coating is obtained every time.” Facility L - OSP

192

Electroless Nickel/Immersion Gold - 2 PWB facilities interviewed Facility M uses Ni/Au on 5% of production; installed a new

line 4 years ago in order to reduce the usage of lead, and to retain business

Facility O uses Ni/Au on 15 to 20% of production; would like to switch to more Ni/Au, but high cost keeps customers from allowing the switch; installed 2 years ago at request of 3 or 4 customers who desired better planarity and stability; converted unused electroless copper line; has led to a substantial increase in business

Increased cycle time, higher scrap than HASL Less maintenance than HASL Increased lab analyses No noticeable improvement in process safety, similar energy

usages

Comparisons to HASL

193

Electroless Nickel/Immersion Gold - 2 assembly facilities interviewed Facility P’s customers like the flat finish and good

press-fit connections;currently 40% of Facility P’s customers use Ni/Au, but that number is decreasing

Facility D found that if the gold is too thin, nickel can oxidize leading to a finish to which solder will not bond; also, if the gold bath is not balanced properly, corrosion of nickel surface will cause a weak joint that is subject to fracturing

Ni/Au boards are difficult to rework - hard to remove nickel layer without damaging board; also, after rework it is difficult to detect problems

Comparisons to HASL

194


“Understand that no technology will be “plug and play.” There must be a commitment from all involved, from manager to equipment operator, to tackle the learning curve and work cooperatively with the supplier. If the new finish is being forced, the resulting resentment will cause the process to turn out poorly. If it is accepted with an open mind by all, then the facility will achieve the cost savings, better planarity, and other benefits that come with the technology.” Supplier - Electroless Ni/Immersion Au

“… training someone who can troubleshoot the equipment and chemistry is a valuable component of the installation process.” Facility O - Electroless Ni/Immersion Au

195

Electroless Nickel/Electroless Palladium/ Immersion Gold - No PWB facilities interviewed

5 installations of this process in US, and 10 worldwide

Mainly being used on an experimental basis

Comparisons to HASL

196

Electroless Nickel/Electroless Palladium/Immersion Gold - 2 Assembly facilities interviewed

Facility Q uses this finish on <1% of production; Likes finish due to wire bondability and solderability

Facility D uses this finish to reduce “black pad syndrome” that is encountered with nickel/gold

Facility Q has found 2 problems - flux incompatibility and intermetallic embrittlement

Facility D has not specified this finish due to volatile pricing of palladium

Comparisons to HASL

197

Summary of Lessons Learned

Thoroughly investigate an alternative surface finish before committing to it

Work closely with the supplier and follow their recommendations

Everyone, top to bottom in the organization, must commit to and participate in the implementation process

Develop a relationship with the end user to ensure that the finish specifications are met

Monitor process control closely Purchase your equipment from suppliers experienced

with the particular surface finish and invest in the correct equipment

198


Industry Representatives PanelDiscussion

199


Closure

200

Requests for Further Information/Publications

DfE PWB Project Web Site: www.epa.gov/dfe/pwb

Order DfE PWB publications through Pollution Prevention Information Clearinghouse phone: (202) 260-1023

fax: (202) 260-4659

email: [email protected]

on the internet: www.epa.gov/opptintr/library/ppicdist.htm

Documents

Design for the Environment Printed Wiring Board Project Presentation of the Surface Finishes Cleaner Technologies Substitutes Assessment (CTSA) Results