MASH2007

Reliability of Solder Joint Quality on J-Lead

Oscillators Using HALT with Lead and Lead

Free Compositions

Steve Laya

Elite Electronic Engineering

Todd Treichel

Precision Devices, Inc.

INTERNATIONAL MICROELECTRONICS AND PACKAGING SOCIETY

MASH2007

Presentation Overview

• Primary Objective: Evaluation of Lead vs. Lead Free

– Use of HALT Vibration (and Thermal Shock)

• Initial Findings

– Sometimes things don’t go as planned…

• Understanding HALT Stresses

• Resonance Dwell To Determine Lead vs. Lead Free

• Post Test Analysis

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Lead vs. Lead-Free

• Conversion from Lead to Lead-Free

– European Union

– Automotive Electronics

– Industrial and Commercial Electronics

• Assure reliability of Lead-Free

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Published Research

• Follow up on

– PDI Testing

– Joint Council on Ageing Aircraft (JCAA)

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J-Lead Ceramic Package Under Test

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Test Vehicle PCB

• 10 parts Lead

• 10 parts Lead-Free

• J-Leaded

Oscillators

• Hand Soldered To

Fiberglass Epoxy

PCB Lead Free Lead

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Electro Ni, 1.78 µm Min.

FR4 Substrate

Cu

Electro Au, 1.00 µm Min.

Kovar, 0.25” Min. Dia.

Tin/Lead SAC 305 Solder

Pb

37% Sn

63% Sn

96.5%

Ag

3.0%

Cu

0.5%

Alloys Under Test

Termination Diagram

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Solder Joint Inspection

NASA-STD-8739.3NASA-STD-8739.3NASA-STD-8739.3NASA-STD-8739.3NASA-STD-8739.3NASA-STD-8739.3

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HALT Table Location

• Placed in the

center of the

HALT vibration

table with Air

Flow evenly

distributed

• Instrumentation

to measure open

circuit on PCB

component

interface.

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Instrumentation

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Elite’s HALT System

• HALT Testing

• 60C/m Temp Shock

• 6-Axis Vibration

• Repetitive Shock

• Power Spectral

Density

Characteristics

• HALT Test Purpose

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6-Axis RS Vibration Table

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Test Results

• Thermal Shock

• Step Vibe

• Sustained Vibration at 50gs

• No failures after 35 hours of vibration

testing.

• How come???

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Perform a Vibration Survey

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Perform a Vibration Survey

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Perform a Vibration Survey

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Measure PCB Resonance

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Lead

Lead-Free 3

2 4

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Resonance Search Run 1

0.1

1

10

10 100 1000 10000

Demand (G)

Ch2 (G)

Ch3 (G)

Ch4 (G)

4 2

3

Gs

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Location # 4

0

2

4

6

8

10

12

1 10 100 1000 10000

Run #2 PCB1 Loc4

Run #3 PCB1 Loc4Run #1 PCB1 Loc4

Location 3 On PCB Near Mounting Bolt

0

0.5

1

1.5

2

2.5

3

1 10 100 1000 10000

Run #2 PCB2 Loc3

Run #3 PCB2 Loc3

Run #1 PCB2 Loc3

Multiple

Searches

Location 4

Multiple

Searches

Location 3 Gs

Gs

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On Chip (PCB2) With and Without Wax

0

1

2

3

4

5

6

7

8

0 500 1000 1500 2000 2500

Run #2 Accel Only

Run #3 Accel + Weight

Measure

resonance of the

Oscillator

Gs

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Location 2 Board 1- Ch4718.8, 23.3

726.2, 9.4

0.001

0.01

0.1

1

10

100

1 10 100 1000 10000 100000

PCB Response from HALT at 51.9g Control

Sw ept Resonance

718.75, 0.543299

0.001

0.01

0.1

1

10

100

1 10 100 1000 10000 100000

HALT Inputl

Sw ept Resonance

PCB Response

4

G2/Hz

G2/Hz

Overlay

resonance on

plot of PSD

Location 4

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0.001

0.01

0.1

1

10

100

1 10 100 1000 10000 100000

Sw ept Resonance

HALT Input

PCB Response

Location 1 Board 2 - Ch3 (Near Bolt)

595.87, 2.00

1,371.88, 9.37

0.001

0.01

0.1

1

10

100

1 10 100 1000 10000 100000

Sw ept Resonancel

PCB Response from HALT at 51.5g Control

G2/Hz

G2/Hz

Overlay

resonance on

plot of PSD

Location 3

3

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Location 2 Board 2 - Ch2784.38, 15.15

0.001

0.01

0.1

1

10

100

1 10 100 1000 10000 100000

Sw ept Resonance

PCB Response from HALT at 51.0gsHALT Response

Location 2 Board 2 - Ch2

0.001

0.01

0.1

1

10

100

1 10 100 1000 10000 100000

Sw ept ResonancePCB Response from HALT at 51.0gsHALT Response HALT Input

G2/Hz

G2/Hz

Overlay

resonance on

plot of PSD

Location 2

2

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Location 2 Board 2 -Ch2 (Center)

784.38, 0.456793

784.38, 15.15

0.001

0.01

0.1

1

10

100

0.1 1 10 100 1000 10000 100000

Series2Series3Series4Series1

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What is the Board Acceleration

• @ 718Hz Location 4 was at 23.3 g2/Hz

• RMS Acceleration at 718 (location 4) is

• Accel = (23.3 x 3.13)1/2 = 8.6g

• @ 1371Hz Location 3, 9.37 g2/Hz

– Accel = (9.37 x 3.13)½ = 5.4g

• @784 Hz Location 2, 15.15 g2/Hz

– Accel = (15.15 x 3.13)½ = 6.8

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Perform Resonance Dwell

• Pick a resonance

• Test to failure

• Determine time to failure

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Lead

Lead-Free 3

2 4

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Lead Free Resonance Dwell at 748Hz

An still no pop-off

failures!

Loc 2

(Gs)

Loc 3

(Gs)

Control

(Gs)

Dwell

(Min)

25 - 3 10

50 - 5.6 10

97 6.3 10 10

217 26 20 10

433 78 40 10

513 106 50 10

560 129 60 7

Total 67

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Solder Joint Inspection 63Sn/37Pb 96.5Sn/3.0Ag/0.5Cu

22% of Joints Fractured 40% of Joints Fractured

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Conclusions & Lessons Learned

• Both constructions are durable

• HALT – Suitable for generating high vibration on PCB

components

– Good fixturing is important

• Resonance Dwell • Concentrates enormous energy at one frequency

• Selection of resonance frequency could skew results.

• Test Uniformity & Repeatability – Difficult to achieve

– Board Resonances

– Locations

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• Any questions

• Thank you!

• Enjoy the remainder of the conference.

INTERNATIONAL MICROELECTRONICS AND PACKAGING SOCIETY