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Transition to Pb-free Products

Dr. Ning-Cheng LeeIndium Corporation of America

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Topics to be DiscussedTopics to be Discussed

• International Electronics Manufacturing Initiative (iNEMI) Overview

• The iNEMI methodology– Roadmapping: Identifying the needs– Gap analysis– Closing Identified Gaps: iNEMI Projects to

Eliminate Pb Solder and implement RoHS

• 2004 Highlights from Environmentally Conscious Electronics (ECE) Roadmap

• Conclusion: Future Challenges

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Mission StatementMission Statement

iNEMI is a member-driven consortium whose mission is to assure leadership of the global electronics manufacturing supply chain for the benefit of its member companies and the industry.

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What Does iNEMI Do?What Does iNEMI Do?

Leverage the combined power of member companies to provide industry leadership

• iNEMI roadmaps the global needs of the electronics industry– Evolution of existing technologies– Predictions on emerging/innovative technologies

• iNEMI identifies gaps (both business & technical) in the electronics infrastructure

• iNEMI stimulates research/innovation to fill gaps• iNEMI establishes implementation projects to eliminate gaps• iNEMI stimulates worldwide standards to speed the

introduction of new technology & business practices• iNEMI works with other organizations to ensure that

government policy recommendations are aligned with our mission.

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7 Product Emulator Groups (PEGs) 7 Product Emulator Groups (PEGs)

Provides Product Requirements for Roadmaps

Emulators Characteristics

Portable / Consumer High volume Consumer Products for which cost is the primary driver including Hand held, battery-powered products driven by size and weight reduction

System in a Package Complete function provided in a package to system manufacturer

Office Systems / Large Business Systems

Products which seek maximum performance from a few thousand dollar cost limit to literally no cost limit

Network / Datacom / Telecom Products

Products that serve the networking, datacom and telecom markets and cover a wide range of cost and performance targets

Medical Products Products which must operate within a highly reliable environment

Automotive Products which must operate in an automotive environment

Defense and Aerospace Products which must operate in extreme environments

Yellow = Completely new Emulator Green = Broadened focus

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2004 Roadmaps 2004 Roadmaps 19 Individual Roadmap Chapters19 Individual Roadmap Chapters

• Semiconductor Technology• Packaging• Mass data storage• Board Assembly• Final Assembly• Environmentally Conscious

Electronics• Interconnect Substrates

Organic• Interconnect Substrates

Ceramic• Connectors

• RF Components & Subsystems• Optoelectronics• Passive Components• Energy Storage Systems• Display • Modeling, Simulation & Design

Tools• Thermal Management• Test, Inspection & Measurement• Product Lifecycle Information

Management• Sensors

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Roadmap AffiliationsRoadmap Affiliations

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Statistics for the 2004 RoadmapStatistics for the 2004 Roadmap

• > 470 Participants• > 220 Companies/organizations• 11 Countries from 3 Continents• 19 Technology Working Groups

(TWGs) (added Sensors)• 7 Product Emulator Groups (PEGs)• Over 1200 Pages of Information• Roadmaps the needs for 2005-2015

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Closing Gaps: Environmental Closing Gaps: Environmental Projects to Eliminate Pb SolderProjects to Eliminate Pb Solder

• 1998 Roadmap identified the technology gap.

• Phase I project developed the alloy, process, components and reliability from 1999-2002.

Results:

– The iNEMI efforts accelerated the establishment of SAC alloys as the standard and reduced the effort in each member company.

• Phase II projects have expanded the technology base to include assembly and rework of large complex PWB assemblies.

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Closing Gaps: Environmental Closing Gaps: Environmental Projects to Eliminate Pb SolderProjects to Eliminate Pb Solder

• 2002 Roadmap identified a number of business Issues to convert to a Pb-free supply chain.

• Five Phase III project teams have addressed these supply chain transition issues.

• Three new Phase IV projects are being established to close recently identified technology gaps:– Wave/selective solder– Mixed assemblies (Pb-free BGA’s in a SnPb assembly

process)– Pb-free surface finishes

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Lead-Free AssemblyChair: Edwin Bradley, PhD Motorola

Co-Chair: Rick Charbonneau

Environmentally Conscious Electronics (ECE) Technology

Integration Group (TIG)

Tin Whisker Accel. TestsChair: Valeska Schroeder, HPCo-Chairs: Jack McCullen, Intel

Mark Kwoka, Intersil

Tin Whisker ModelingChair: George Galyon, IBMCo-Chair: Maureen Williams, NIST

Tin Whisker Users GroupChairs: Joe Smetana, Alcatel

Richard Coyle, Lucent

RoHS Transition Task GroupChair: Dave McCarron, Dell

Projects: Component Supply Chain Readiness

Chair: John OldendorfComponent and Board Marking

Chair: Vivek Gupta, IntelAssembly Process Specifications

Chair: Frank Grano, -SCIMaterials Declarations

Chair: Nancy Bolinger, IBM

Complete

Pb-free BGAs in SnPb Assy.

Chair: Robert Kinyanjui, Sanmina-SCI

Pb-free Wave Soldering Chair: Denis Barbini, Vitronics Soltec,

Co-chair Paul Wang, Sun Microsystems

Lead-Free Assembly & ReworkChairs: Jerry Gleason, HP

Charlie Reynolds, IBM

Team Leaders: Jasbir Bath, Solectron,Quyen Chu, Jabil CircuitMathew Kelly, CelesticaKen Lyjak, IBMPatrick Roubaud, HP

Lead-Free Assembly & ReworkChairs: Jerry Gleason, HP

Charlie Reynolds, IBM

Team Leaders: Jasbir Bath, Solectron,Quyen Chu, Jabil CircuitMathew Kelly, CelesticaKen Lyjak, IBMPatrick Roubaud, HP

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*Definition of IPC Assembly Classes*Definition of IPC Assembly Classes

• Class 1- General Electronic ProductsIncludes consumer products, some computer and computer peripherals suitable for applications where cosmetic imperfections are not important and the major requirement is function of the complete electronic assembly.

• Class 2- Dedicated Service Electronic ProductsIncludes communications equipment, sophisticated business machines and instruments where high performance and extended life is required and for which uninterrupted service is desired but not critical. Certain cosmetic imperfections are allowed.

• Class 3- High Performance Electronic ProductsIncludes the equipment where continued performance or performance-on-demand is critical. Equipment downtime cannot be tolerated and must function when required, such as in life support devices or flight control systems. Assemblies in this class are suitable for applications where high levels of assurance are required, service is essential, or the end-use environment may be uncommonly harsh.

*From IPC-A-610C, January 2000

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Phase I PbPhase I Pb--Free Project ResultsFree Project Results

Phase 1 Focused on IPC Class 1 Products• Solder Alloy

– Recommended Tin-Silver-Copper alloy for reflow and Tin-Copper alloy for wave soldering

– Backwards compatible with lead based systems

• Components– Maximum component temperatures of 240C for large ICs,

250C max for small ICs on boards ≤ 0.92” thick were achieved

– JEDEC revised J-STD-020B standard 250°C –5/+0

• Process– Manufactured with existing assembly process equipment– Performance of Pb-free pastes and fluxes are adequate

• Reliability– Demonstrated Pb-free joints are more reliable than tin-lead

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PbPb--Free Phase I Project ResultsFree Phase I Project Results

–iNEMI declares victory for lead-free alloy• In 2000, NEMI team recommended

Sn3.9Ag0.6Cu for reflow solder• Many other compositions have been

proposed, but debate has shifted from a wide variation of materials to discussion of best SnAgCu alloy

• Although compositions vary, the iNEMI-recommended alloy is representative of the acceptable range of lead-free alloys

– Provides a model system for industry that has been extremely well-characterized by iNEMI and NIST

– Members are using the alloy in production• iNEMI’s focus on a single lead-free alloy

helped accelerate industry convergence on standard solder formulations and manufacturing processes

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Phase I PbPhase I Pb--Free Project ParticipantsFree Project ParticipantsOEM/EMS Solder Supplier Equipment

OthersComponent

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Phase II PbPhase II Pb--Free ProjectsFree Projects

• Lead-Free Assembly & Rework – Assembly Process Development– Reliability– Rework Process Development– Components & Materials

• Tin Whiskers Accelerated Test • Tin Whisker User Group• Tin Whisker Modeling

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PbPb--Free Assembly & ReworkFree Assembly & Rework

Objective:Develop baseline manufacturing process for medium to high-end IT

products (IPC Class 2) in time to meet EU RoHS requirements Scope:Extend the previous project’s work (based on SnAgCu solder) into

new areas:– High I/O count packages– Large thick PWBs– Rework– MSL limits (for large complex PWBs)

Status: – Existing rework process needs additional development to meet

maximum temperature requirements for lead-free packages and laminates

– Group has revised process and tools to stay under the maximum temperature goal of 260°C

– Reliability testing complete– Final report being written

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PbPb--Free Assy & Rework ParticipantsFree Assy & Rework Participants

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PbPb--free Assy & Rework Organizationfree Assy & Rework Organization

Project ManagementJerry Gleason, HP

Charlie Reynolds, IBM

Assembly ProcessDevelopment

Matt Kelly, Celestica

Rework ProcessDevelopment

Jasbir Bath, SolectronQuyen Chu, Jabil Circuit

Process Robustness Assessment /

Reliability TestsPatrick Roubaud, HP

Logistics, Procurement,

Documentation,Ken Lyjak, IBM

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Assembly Team DeliverablesAssembly Team Deliverables

Assembly Process:space

(a) Define process windows for IPC Class 2 assemblies.

space

(b) Determine absolute minimum solder joint temperature during reflow.

space

(c) Quantify differences between surface finish & card thickness.

space

(d) Minimize ∆T across IPC Class 2 assemblies & minimize maximum peak temperatures.

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Assembly Team DeliverablesAssembly Team Deliverables

Laminate Performance Assessment:space

(e) Develop pre-conditioning method to determine laminate survivability during entire process.

space

(f) Perform IST and CITC testing after Pb-free temperature pre-conditioning stress.

space

(g) Compare IST and CITC test methods.space

(h) Assess one potential laminate material for survivability.

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Assy/Rework Cumulative DamageAssy/Rework Cumulative Damage

SMT ReflowBottom Side

SMT ReflowTop Side

Wave Solder

1X Rework

2X Rework

Cum

ulat

ive

Hea

t Exp

osur

e / D

amag

e

Process Flow Complexity

Cumulative Effect on Components& Boards is significant through entire assembly process.

1 assembly can be exposed to as many as 5 thermal heat excursions.

Component issues include increased MSL sensitivity, shorter floor life, and internal package failure.

PCB issues include internal layer delamination, via cracking and board warpage.

Single Assembly Heat Excursions

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Assy Team RecommendationsAssy Team Recommendations

1. IPC Class 2 Pb-free SMT reflow processing windows will shrink. (Windows identified)

2. Multiple heat cycles cause significant component and laminate stress. Stress management is essential.

3. Reflow in air was shown to produce properly formed joints.

4. The use of N2 was shown to promote wetting, and create shinier looking joints.(Improved aesthetics).

5. Coldest Solder joint on ANY Pb-free assembly should be no less than 230°C.

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Rework Team ObjectivesRework Team Objectives

• Develop a lead-free rework process for area array packages (uBGA, PBGA, CBGA) using conventional hot air gas rework system on mid to high end server boards.

• Investigate the feasibility of lead-free pin-through-hole (PTH) DIP component attachment rework process on mid to high end server boards.

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Rework Profile ComparisonRework Profile Comparison

• Minimum Lead-free solder joint temperature (230°C)

• Package temperature was close to the limit of max body temperature allowed

• Extended profiles for Lead-free (Avg: ~35% longer)

135mil Thick Profile Parameters

Min. Joint Temp (C)

Package Temp (C)

Time to Peak (sec)

Min. Joint Temp (C)

Package Temp (C)

Time to Peak (sec)

CBGA 201 202 580 235 238 675

uBGA 199 210 300 229 245 450

PBGA 200 220 450 230.3 247 650

PackageSnPb SAC

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Rework Key Challenges Rework Key Challenges

• Lead-free PTH Rework– Without board preheat, achieving “good/sufficient”

holefill resulted in copper pad erosion– Maintaining a desirable copper level in the minipot

• Lead-free BGA Rework– Difficult to minimize top package temperature while

allowing sufficient minimum peak solder joint temperatures

– Adjacent and bottom side components undergoing a secondary reflow

– Equipment not optimized for Lead-Free rework

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Phase II PbPhase II Pb--Free Project ResultsFree Project Results

Phase II Focused on IPC Class 2 Products • Solder Alloy

– All work based on iNEMI SAC Alloy

• Components– Component temperatures of 230C - 260C max on boards 135 mil.

thick were observed– PWB material selection is critical (for thick, complex boards)!– JEDEC revised J-STD-020C standard (260°C max. component

temp.)

• Process– Manufactured with existing assembly process equipment– Developed rework capability for SAC (more effort needed)

• Reliability– Demonstrated reliability of high I/O count devices on complex

boards (with & without rework)– No impact – electrolytic NiAu vs. Immersion Ag

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Tin Whisker Accelerated TestTin Whisker Accelerated Test

Objective:

The Tin Whisker Accelerated Test Project is an open program to devise industry standard tests for predicting tin whiskers

Status:–The group has carried out two factorial experiments looking for test methods involving :

• Temperature• Humidity• Thermal cycling

–Third test passed 9000 hours; report at ECTC May 31, 2005–Fourth test planned to verify voltage effect is underway–Fifth test defined to develop acceleration factors now starting

Example of tin whisker

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Tin Whisker Accelerated TestTin Whisker Accelerated Test

Status (continued):

– Developed and submitted tin whisker “test protocol” to IPC/JEDEC for consideration as an industry standard:

• Defines a tin whisker• Defines methods of measuring and cataloguing whiskers• Recommended tests on which industry can collect data even

though cannot quantify test results

– Status: iNEMI project chair drove development of JESD 22-xxx, currently out for vote.

– Group is coordinating with JEITA (Japan) and ITRI/E4 (Europe) to establish unified whisker test methods worldwide, including pass/fail criteria and fields of application

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Tin Whisker Test TeamTin Whisker Test Team

• ITRI Soldertec• Micro Semi• Soldering Tech.

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Tin Whisker ModelingTin Whisker Modeling

Objective:To determine the mechanism of tin whisker formation and growth so that we can predict behavior, design mitigation methods, and develop acceleration testsStatus:

– 1st Workshop (iNEMI/NIST/TMS) at Metals, Minerals and Materials Society conference San Diego, March, 2003

– Interim report produced in June 2003– 2nd Workshop (iNEMI/CPMT/ECTC) held at ECTC in Las

Vegas, June 2004– IEEE Mfg. Transactions special edition in development– 3rd Workshop (iNEMI/CPMT/ECTC) to be held at ECTC in

Orlando, May 31, 2005

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Tin Whisker Modeling ParticipantsTin Whisker Modeling Participants

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Tin Whisker User GroupTin Whisker User Group

Objective:iNEMI formed the Tin Whisker User Group to develop recommendations for lead-free surface finishes on components that would minimize risk of failures from tin whiskers in high-reliability electronic applications.

Status:– Group compared approaches, reviewed literature and issued

interim report on mitigation strategy, March 2004. (Update to be released by March 31, 2005).

– Developed Acceptance test and proposed to JEDEC/IPC for industry standard.

– Working with JEDEC Task Group to publish Acceptance Specification (goal: document ready for vote March 31, 2005).

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Tin Whisker User GroupTin Whisker User Group

• Large corporate users of components–Concerned with long-term reliability (>8 years)

• Developed recommendations for mitigating impact of tin whiskers on high-reliability products

–Use of nickel-paladium or nickel-paladium-gold instead of tin–Use of nickel underlay–Heat treatment (150°C for 1 hour)–Reflow the tin coating

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Tin Whisker User Group ParticipantsTin Whisker User Group Participants

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Phase III: Phase III: RoHS Transition ProjectsRoHS Transition Projects

Objective:

The RoHS Transition Task Group is working to address a number of supply chain and logistics issues related to the transition away from banned substances.

Scope: • Identify projects • Determine if industry standardization is appropriate • Develop standards requirements• Identify appropriate standards body• Work with standards body to develop and deploy standard

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RoHS Transition Task GroupRoHS Transition Task Group

Five projects have been organized to

–Assembly Process Specifications–Component and Board Marking (including product number change management and labeling standards) JEDEC, IPC–Component Supply Chain Readiness–Materials Declarations–Materials Composition Data Exchange

address the following:

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Phase IV: Phase IV: PbPb--free Soldering Technology Projectsfree Soldering Technology Projects

Objective:

Address several recently identified technology gaps

Status:

Two projects are underway: – Pb-free Wave Soldering Assembly Process– Substrate Surface Finishes for Lead-Free Assembly

Third project being formed:- Pb-Free BGA’s in SnPb assembly process

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PbPb--free Wave Soldering Assemblyfree Wave Soldering Assembly

Objective:Characterize the impact of lead-free on wave and

selective soldering processes

Scope:Understand lead-free wave/selective solder assembly

including:– Optimum alloy selection– Process parameters – Product reliability – Equipment implications

Status: – SOW defined, project plan out to membership for sign

up.– Test Vehicles designed, Boards delivered.– TV Build to begin shortly.

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Wave Solder ParticipantsWave Solder Participants

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The 2004 iNEMI RoadmapThe 2004 iNEMI Roadmap

• Broader International Participation–IEEE CPMT

• Released to public at Apex on February 22, 2005• Highlights from the 2004

Environmentally Conscious Electronics (ECE) Roadmap –New organization of the chapter

• Design • Energy• Recycling• Materials• Sustainability

–Broader Input

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Gaps and Needs: Design Gaps and Needs: Design

Design For Environment (DFE) is being Integrated at the beginning of Design Cycle

• Automated data management systems for materials declarations

• Qualification of acceptable replacements for hazardous substances

• Product compliance verification testing • Life Cycle Analysis (LCA) tools • WEEE compliance verification process

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Gaps and Needs: EnergyGaps and Needs: Energy

Minimizing energy consumption is a major focus for electronic equipment manufacturers

• Cost efficient methods to improve the energy efficiency of power supplies

• Enabled power management of IT equipment

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Gaps and Needs: Materials Gaps and Needs: Materials

New trends in environmental regulations of materials pose challenges as well as opportunities for industry

• RoHS Definition of Homogeneous Materials• Pb-free for high reliability requirement applications• Cd and Pb-free PVC cables• REACH risk assessment for chemical emissions

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Gaps and Needs: RecyclingGaps and Needs: Recycling

Globally, the electronics industry is being required to take responsibility for its products at the end of life

• Recycling Technologies• Laws, policies, and procedures to support electronic

component recovery and reuse• Operational support systems for recycling

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Gaps and Needs: Sustainability Gaps and Needs: Sustainability (Metrics)(Metrics)

The iNEMI ECE TWG identified sustainability as a new focus area for the Roadmap

• Definition of Sustainability • Standard Sustainability Indicators and Reporting protocols

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Future Challenge to the IndustryFuture Challenge to the Industry

• Green Electronics

– As we recover from the recession and from implementing RoHS and WEEE, the electronics industry needs to develop a strategic vision of sustainable electronics.

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www.inemi.orgwww.inemi.orgEmail contacts:Email contacts:

Jim McElroy Jim McElroy

jmcelroy@inemi.orgjmcelroy@inemi.org

Bob PfahlBob Pfahl

bob.pfahl@inemi.orgbob.pfahl@inemi.org