Post on 13-Oct-2020
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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