iNEMI Pb-Free Electronics

Activity

Bob Pfahl

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iNEMI Today

International Electronics Manufacturing Initiative (iNEMI) is an industry-led

consortium of 100 global manufacturers, suppliers, industry associations,

government agencies and universities. A Non-Profit Fully Funded by Member

Dues; In Operation Since 1994.

Visit us at www.inemi.org

5 Key Deliverables:

• Technology Roadmaps

• Collaborative Projects

• Research Priorities Document

• Proactive Forums

• Position Papers

3 Major Focus Areas:

• Miniaturization

• Environment

• Medical Electronics

Mission: Forecast and Accelerate improvements in the Electronics

Manufacturing Industry for a Sustainable Future.

iNEMI Projects for Pb-free Electronics

Meeting the

requirements of

the EU RoHS

Directive

1998-Today

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iNEMI and the Environment: 1998-Present

• Since 1996 iNEMI has proactively roadmapped the

technology needs to produce Environmentally Conscious

Electronics (ECE)

• iNEMI members have provided the technical and supply

chain leadership to meet the EU directives on Electronic

Products.

– iNEMI and NIST performed the research to identify the

preferred solder to replace Sn-Pb

– iNEMI developed the processes and standards for the

conversion

– iNEMI developed the standards for environmental data transfer

4

Pb-Free Electronics-Actions Required

• Research to identify viable alternatives

• Reliability studies on alternatives

• Selection of single alloy

• Process Development

• Material development (paste and flux)

• Application Development

• Identify the reliability risk of potential “whisker”

growth from pure tin plating on components

• Reliability of solutions are still being verified

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Pb-free BGAs in SnPb Assy.

Chair: Robert Kinyanjui, Sanmina-SCI

Pb-free Substrate Finishes

Chair: Keith Newman, Sun Microsystems

Co-chair: Charan, Gurumurthy, Intel

Pb-free Wave Soldering

Chair: Denis Barbini, Vitronics Soltec

Co-chair: Paul Wang, Microsoft

Tin Whisker Modeling Chair: George Galyon, IBM

Co-Chair: Maureen Williams, NIST

Tin Whisker Users Group Chairs: Joe Smetana, Alcatel

Richard Coyle, Lucent

Pb-Free Assembly Chair: Edwin Bradley, PhD Motorola

Co-Chair: Rick Charbonneau

Environmentally Conscious

Electronics Projects

Tin Whisker Accel. Tests Chair: Heidi Reynolds, Sun Microsystems

Co-Chairs: Jack McCullen, Intel

Mark Kwoka, Intersil Pb-Free Assembly & Rework

Chairs: Jerry Gleason, HP

Charlie Reynolds, IBM

Team Leaders: Jasbir Bath, Solectron,

Quyen Chu, Jabil Circuit

Mathew Kelly, Celestica

Ken Lyjak, IBM

Patrick Roubaud, HP

RoHS Transition Task Group

Chair: Dave McCarron, Dell Projects:

Component Supply Chain Readiness

Component and Board Marking

Assembly Process Specifications

Materials Declarations

Mat. Declaration Data Exchange

Chair: Richard Kubin, E2open

Co-chair: Marissa Yao, Intel

iNEMI Lead-Free Alloy Alternatives

Project Update

July 2012

Chair: Elizabeth Benedetto, HP

Project Team Members

19 companies; 66 individuals

Solder alloy suppliers, component suppliers, EMS providers, OEMs

Near-eutectic SAC allowed industry to meet

RoHS deadline of July 1, 2006

• Industry adopted SAC 305 & other “near eutectic” alloys as the standard Pb-free alloys during the RoHS transition

• Selected by industry consortia balancing many factors

• Major factors included:

– Relatively low melting point

– Reasonable thermal fatigue reliability

• Selected prior to understanding impact of composition on mechanical robustness and copper dissolution

Typical Sn-Ag-Cu (SAC)

microstructure

Problems with SAC305/405 include:

• Poor drop/shock performance for

BGAs, especially on Ni/Au surfaces

• Expense of Ag is driving the desire to

reduce Ag content

– $430/lb – July 23, 2012

(Tin ~ $8.60/lb)

– Wave solder bar main concern

• Poor barrel fill on thick boards for

some surface finishes

• Copper dissolution

• Hot tearing and other surface

phenomena create inspection issues &

possibly unnecessary rework

Ni

Cu

Solder

IMC

Fracture surface showing intermetallic

layer left, no solder

Gregorich, et al., IPC/Soldertec Global 2nd International

Conference on Lead Free Electronics (2004).

SAC305/405 functional but not the optimal

Pb-free solution

Reduced Ag content may reduce thermal

fatigue resistance but more work needed

• Major gap in industry knowledge

• Small number of studies;

conflicting data

• Performance of low Ag alloys

relative to Sn-37Pb not clear

• Impact of microalloy additions

unknown

• Impact of alloy composition on

the acceleration factor unknown

– Relates accelerated test life to

life in the field

Henshall et al., APEX 2009

Thermal fatigue crack

SAC105 ball

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Impact of alloy

composition on thermal

fatigue life in the field

difficult to judge

Low Ag alloys may perform worse than high Ag

alloys but impact of dopants not known

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0/100 C

10 min. dwells • 2512

Resistors

• SAC405,

305, 205,

105 &

Sn-Cu

• Thermal

fatigue life

increases as

Ag content

increases

Data of Coyle et al., ECTC 2009

Overview of Industry Efforts

• Generate data to predict alloy thermal fatigue performance

Industry

Working Group

Alcatel-Lucent

Working Group

Jabil Working

Group

iNEMI Alloy

Characterization

Impact of Ag concentration Impact of Ag concentration & dopants

Rapid results

through using

existing test

materials

Comparison to Sn-Pb

Mixed Sn-Pb/Pb-free joints Data for common

commercial alloys

Effects of thermal cycle profile Quantitative

acceleration factors

Impact of package type

iNEMI : Alloys under test

• 12 Pb-free alloys plus

Sn-Pb control

• Systematically investigate

impact of Ag content

• Impact of common dopants,

such as Ni

• Alloys becoming fairly

common in practice

• Impact of aging

No. BGA Ball Alloy Trade Name

Solder

Paste Comments

1 Sn-37Pb Eutectic Sn-Pb Sn-37Pb Control

2 Sn-0.7Cu+0.05Ni+Ge SN100C SN100C 0% Ag joint

3 Sn-0.7Cu+0.05Ni+Ge SN100C SAC305 Impact of [Ag]

4 Sn-0.3Ag-0.7Cu SAC0307 SAC305 Impact of [Ag]

5 Sn-1.0Ag-0.5Cu SAC105 SAC305 Impact of [Ag]

6 Sn-2.0Ag-0.5Cu SAC205 SAC305 Impact of [Ag]

7 Sn-3.0Ag-0.5Cu SAC305 SAC305 Impact of [Ag]

8 Sn-4.0Ag-0.5cu SAC405 SAC305 Impact of [Ag]

9 Sn-1.0Ag-0.5Cu+0.05Ni SAC105+Ni SAC305

Impact of

dopant

10 Sn-2.0Ag-0.5Cu+0.05Ni SAC205+Ni SAC305

Impact of

dopant

11 Sn-1.0Ag-0.5Cu+0.03Mn SAC105+Mn SAC305

Impact of

dopant

12 Sn-0.3Ag-0.7Cu + Bi SACX0307 SAC305

Doped

commercial

alloy

13 Sn-1.0Ag-0.5Cu SAC105 aged SAC305 Effect of aging

14 Sn-3.0Ag-0.5Cu SAC305 aged SAC305 Effect of aging

15 Sn-1.0Ag-0.7Cu SAC107 SAC305 Impact of [Cu]

16 Sn-1.7Ag-0.7Cu-0.4Sb SACi SAC305

Doped

commercial

alloy

iNEMI: Thermal cycle test overview

Test Profiles and

Status as of July 2012

• Two package types

• 192 CABGA

• 84 CTBGA

• Full factorial structure for

determination of acceleration

factors

• Impact of Tmin, Tmax, T,

and dwell time

• Interactions among the

three main variables

(Tmax, T, dwell time )

• Two additional profiles

• Long dwell

• Test alloys for harsh

environment applications

– Auto, aerospace, military

Began cycling: March 2011

Est. completion: Dec. 2012

Company Cycle (Min/Max/Dwell)

Date Started Cycling Current Cycle #

ALU A) 0/100/10 3/21/2011 12900

ALU E) 0/100/60 2/10/2011 6100

CALCE H) -15/125/60 5/2/2011 2585

CALCE H') -40/100/120 6/15/2011 1579

Delphi Z) -40/125/10 8/24/2011 Complete

Henkel C) -40/100/10 7/27/2011 6200

HP F) 25/125/60 5/12/2011 3911

HP G) -40/100/60 5/31/2011 3554

IST B) 25/125/10 7/22/2011 Complete 9946

Nihon D) -15/125/10 8/3/2011 5200

Lack of test standards creates risk

and slows adoption of new alloys • Risks of not having standard test data

– High melting point alloys will shrink an already small process window; need data to establish practical process limits

– Alloys formulated to meet specific goals not consistently tested to determine general suitability

• Example: low-Ag alloys tested for improved mechanical shock performance but thermal fatigue reliability not evaluated

• Risks of not having standard test methods

– Data from one valid experiment may not be comparable to another (data not “portable”)

– Test results may not directly correlate with OEM concerns

• Data must enable alloy acceptability decisions

– Example: Bulk properties not sufficient to predict solder joint thermal fatigue life

Incomplete solder joint formation

for a 1% Ag ball alloy assembled

at the low end of typical Pb-free

reflow process window.

CSP Package

CSP Package

PCB

PCB

Multi-step process for developing industry

standard alloy tests

Individual Company

Specifications

iNEMI Recommendations

Align with SPVC

Develop IPC standards

SPVC = Solder Products Value Council (solder suppliers)

Status of industry standards development for

testing of new alloys

Basic Material

Properties

Board-Level

Reliability

Impact on Mfg.

Process

iNEMI

Recommendations

Complete Complete Started

Alignment of

iNEMI and

SPVC/IPC

Recommendations

Nearly

Complete

Pending Not Started

IPC Standards

Development

Pending Early Draft Not Started

Summary and conclusions (1 of 2)

• Based on our earlier assessment of key knowledge gaps, the iNEMI Characterization of Pb-Free Alloy Alternatives Project is focused in two areas:

– 1. experiments to establish the long term thermal fatigue reliability of a wide variety of alloys

– 2. standardizing information requirements and test methods for

alloy acceptability assessments

• Thermal cycle experiments address five areas of concern.

– Validate the impact of Ag concentration

– Evaluate the impact of commercially common dopants

– Assess how alloy composition affects the acceleration behavior

– Provide basic thermal fatigue data for common alternate alloys

– Assess the performance of some new commercial and experimental alloys

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Summary and conclusions (2 of 2)

• Currently testing 12 different Pb-free alloys plus a Sn-37Pb control using

ten thermal cycle profiles and two different sized organic BGA packages.

Initial publication of results is planned for SMTAI 2012.

– The iNEMI team has an entire session scheduled for SMTAI 2012, where

four papers will be presented outlining the work and current results.

– Additional presentations are scheduled for ESTC in Amsterdam, and IEMT

and IMPACT in Asia.

• Development of standard test requirements and methods continues.

Several areas of consensus appear to be emerging, and formal

discussions with the IPC on establishing test standards are ongoing.

Three separate standards in development or planned:

– Basic material properties

– Impact to PCA reliability

– Impact to PCA manufacturing

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Postscript: Current Changes

impacting Commercial Electronics Reliability

Creep Corrosion - Phase 3

Chair: Xiaodong Jiang,

Alcatel-Lucent

Co-Chairs: Mason Hu, Cisco;

Simon Lee, Dow Chemical

Project Chair: Project Co-Chair:

Strategy Tactics Start: Anticipated End:

Issues Graphics

Focus Area:

Aug-12 TIG:

Goal: To collect the environmental pollution related creep corrosion failures from the global electronics industry

Miniaturization

Board Assembly

Creep Corrosion – Phase 3

Mason Hu, Cisco; Simon Lee, Dow Xiaodong Jiang, Alcatel-Lucent

• Due to RoHS transition, the SnPb based PWB finish will move to Pb-free compatible finishes

• Corrosion of electronics in many areas in Asia

• However, there is very little agreement on the test methods and conditions

• This project seeks to establish a standard test methodology to facilitate further investigation of this problem.

• Survey of the occurrence of creep corrosion in the industry

• Inclusive of global applications

• Investigation of environmental conditions related to creep corrosion (temperature, relative humidity, atmospheric concentration of sulfide)

• Investigation of the surface finishes related to creep corrosion

• Investigation of manufacturing factors related to the incidence of creep corrosion (e.g. flux, processing, operations)

• Due to RoHS transition, the SnPb based PWB finish will move to Pb-free compatible finishes

• Corrosion of electronics in many areas in Asia

• However, there is very little agreement on the test methods and conditions

• This project seeks to establish a standard test methodology to facilitate further investigation of this problem

4-11 3-12

Copper Wire Bonding

Reliability

Chair:

Peng Su,

Cisco Systems

Project Chair: Project Co-Chair:

Strategy Tactics Start: Anticipated End:

Issues Graphics

Focus Area:

Aug-12 TIG:

Goal: Understand key issues and concerns regarding reliability of Cu wire bonding for semiconductors

Miniaturization

Packaging

Copper Wire Bonding Reliability

-- Peng Su, Cisco

• Phase 1

• 1. Industry Survey

• 2. Existing data review

• 3. DOE Plan for Phase 2

• Phase 2

• 1. Finalize DOE

• 2. Procure Materials

• 3. Package Assembly

• 4. Reliability Tests

• 5. Failure Analysis

• 6. Summary

• 2-phased project. The first phase will focus on collecting information from the industry regarding the key processing and reliability issues pertaining to Cu wire bonding. The second phase of the project will perform necessary experimental work in the areas as defined by Phase 1

• Copper bond wires are increasingly being used for a wide variety of components.

• Reliability needs to be collectively assessed by the industry in a quantitative manner.

• Standard reliability test methods and durations for Au wire device may not be sufficient for Cu

10-10 12-11

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www.inemi.org Email contacts:

Dave Godlewski

dgodlewski@inemi.org