Post on 14-Apr-2022
1 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
APEX 2007Reliability Summit
“Keeping industry reliability test protocols current with rapidlychanging markets”
CALCE and CALCE Pb-freeResearch Activities
ISO 9001:2000Certified, 1999
Formed 1987
Michael Osterman, Ph.D.osterman@calce.umd.edu
Center for Advanced Life Cycle EngineeringUniversity of MarylandCollege Park, MD 20742
(301) 405-5323http://www.calce.umd.edu
2 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
What is CALCE?Center for Advanced LifeCycle Engineering(founded 1987) is dedicatedto providing a knowledgeand resource base tosupport the developmentand sustainment ofcompetitive electroniccomponents, products andsystems.
Areas of research
• Physics of Failure• Design of Reliability• Accelerated Qualification• Supply-chain Management• Obsolescence• Prognostics
~24 Faculty and Research Staff~20+ M.S. students~60+ Ph.D. students
CALCECALCEElectronic Productsand Systems Center
~$5M/Year
CALCECenter for Advanced
Life Cycle EngineeringRisk Mgmt in
Avionics Systems
• Manufacturing for sustainment(USAF ManTech Program)
• IEC and avionics workinggroup collaboration
LabServices
• Small jobs• Fee-for-service• Proprietary work• Use of CALCE Tools &
Methods• Turnkey capabilities• “Fire-fighting”
MEMSTechnology
• Combined RF MEMS andSi/Ge Hetrojunction BipolarTransistors (HBTs)
• MEMS chip-to-chip
bonding reliability
ResearchContracts
• Larger programs• Some past programs:• Power Electronics (Navy)• Embedded Passives (NIST)• Risk Management (USAF)• Life Assessment (NASA)• MEMS (NASA,NSWC)
• Risk assessment, mitigationand management of electronicproducts and systems
CALCEElectronic Products
and SystemsConsortium
EPSConsortium
• 40-45 companies• Pre-competitive research• Risk assessment,
management, andmitigation for electronics
http://www.calce.umd.edu
• Risk assessment, mitigationand management of electronicproducts and systems
CALCEElectronic Products
and SystemsConsortium
PHMConsortium
• Pre-competitive research• Research in fundamental
methodologies to developand implement prognosticsand health managementsystems.
Education• MS and PhD EPS
program• International visitors• Web seminars• Short courses for
industry• Publications
Long-termPb-free Reliability
Study• Aging• Intermetallic formation• PCB surface finish• ECM• Solder interconnects
3 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
CALCE Consortia Members
• Arbitron• Aavid Thermalloy
• ACEL, China
• Argon
• B & G , Sequel, CA
• BAE Systems
• Beihang University, China
• Boeing• DBD, Germany• Defense Logistics Agency• Dell Computer Corp.• EADS CCR, France• Emerson• EMC Corp.• Ericsson AB, Sweden
• ERS
• Faraday
• GCAS
• General Dynamics, AIS
• GE Corp.
• Goodrich Engine Control,
UK
• Grundfos, Denmark
• Hamilton Sundstrand
• Harris Corp.
• Hewlett-Packard Co.
• Honeywell
• Instit. Nokia de Tecnologia, Brazil
• Lutron
• Medtronic, Inc.
• Mercury Computer Systems
• Motorola
• NASA
• NAVAIR
• Northrop Grumman Corp.
• Naval Surface Warfare Center
• Nokia Research Center, Finland
• Philips Electronics, The Netherlands
• Qualmark
• QinetiQ Aquila, UK
• Reactive Nano Tech
• Research In Motion, Ltd., Canada
• ReliaSoft Corporation
• Rockwell Collins, Inc.
• Rolls Royce
• SAIT, Korea
• Samsung Memory, Korea
• Samsung Techwin Co., Ltd.,
Changwon-si, Korea
• Sandia National Labs
• Schlumberger Oil Field Services
• Seagate Technology Inc.
• Siemens AG, Germany
• Smiths Aerospace
• Sun Microsystems (StorageTek),
• Tessera
• TRW Automotive, UK
• Toshiba, Japan
• U.S. AMSAA
• U.S. Army Research Lab.
• U.S. Army Picatinny
• Whirlpool Corp.
4 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
CALCE Test Services and Failure AnalysisCALCE Test Services and Failure AnalysisLaboratoryLaboratory
ServicesServices• Benchmarking of part and contract manufacturers
• Review of mechanical and electrical design
• Review of failure-mode mechanisms andeffects-analysis (FMMEA)
• Recommendations for accelerated life testing
• Accelerated testing to determine product robustness
• Virtual qualification and reliability assessment
• Identification of critical-to-quality parameters
• Materials characterization
• Failure analysis and uncovering new failures
– Electrolytic capacitor failures due to aqueous electrolyte formulation
– Vertical filament formation (VFF)
– Cracking in base metal electrode (BME) ceramic capacitors in humidenvironments
Failure ofelectrolyticcapacitors
Failure ofPWB due
to VFF
5 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
CALCE EP&S Consortium Research ProgramCALCE EP&S Consortium Research Program
Research Program Theme(Identification and development oftechnologies, methodologies, andguidelines for assessing, mitigating, andmanaging the risks associated with thedesign, manufacture and fielding ofelectronic products and systems)
FailureIdentificationand ReliabilityModeling
Research RoadmapThrust Areas
FY07 Research Areas
Risk-informedTechnologyInsertionMethodologies
Environmentaland OperationalAssessment ofProducts
Pb-free Electronics
Failure Mechanisms
New Technologies, Materials andProcesses
Virtual Qualification
Part Management and Sustainment
Thermal Design and Management
6 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
CALCE EPSC Pb-free Research
Solder material testing (constitutive and durability properties)NCMS (4 solders)Sn/3.9Ag/CuSn/AgSn/CuOthers (Sn-In/Bi/Zn/Al/Sb/3.0Ag/?)
PWB/component finish & interface integrity (OSP, Imm Au/Ag/Sn, Au/Ni, HASL,SnPb) (Mixed technology issues eg Pb-contamination; Post-aging tests)
Overstress (ball shear, PWB flexure, shock)Cyclic durabilityNoble platings and creeping corrosionWhiskering
Connector fretting corrosionConductive and nonconductive adhesives
Soft particles (Au-plated polymers)No particles
Accelerated testing (SnAgCu, ?, multiple finishes, mixed tech, pre-aging)Thermal cycling/shockVibrationCombinationsMechanical shock/impactHumidity
Virtual qualification software/Model calibrationManufacturing/Rework QualityBusiness risk assessment, IP & liability issues
Virtu
al
qu
alifica
tion
,D
esign
trad
eoffs
Accelera
tedtestin
g,
Hea
lthm
on
itorin
g
---------96 97 98 99 00 01 02 03 04 05 06
7 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
CALCE Pb-free Solder Temperature CyclingReliability Testing
• Solders Completed– Indium SMQ 230 Sn95.4/Ag3.9/Cu0.7– Indium SMQ 230 Sn96.5/Ag3.5– Indium SMQ 92J Sn63/Pb37
• Solder Under Test– Aim SN100C Sn/Cu/Ni(.5) w/254 flux– Aim SAC 305 w/254 flux
– Indium SMQ92J Sn61.5/Pb 36.5/Ag2
Test details• 16 samples in each test condition• Resistance of each chip is monitored by a data
logger.• Temperature is recorded at the center of each
card.• Test continues until 100 % failure occurs.• Cross sectioning was performed on failed test
specimens to verify a solder interconnect failure.
Packages Under Test• 68-pin LCCC: 24mm 24mm• 84-pin LCCC: 30mm 30mm• PCB Board: 130 x 93 x 2.5 mm,FR4
8 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Experimental Test Matrix
Completed757085158
Completed1510050-509#
85
100
125
75
125
75
100
Max.Temp.(C)
Completed1570157
Completed7510006
Completed75100255
Completed
Completed
Completed
Completed
Status
75
15
15
15
Dwell Timeat Max
temp* (min)
10004
100253
100-252
10001
Temp.range(C)
Min.Temp.(C)
Test
*Dwell at minimum temperature is set to be 15 minutes.# SnPb had only four cards
9 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Test Results for Tmean = 50oC, T=100oC
x 10x
1.00
5.00
10.00
50.00
90.00
99.00
Probability - Weibull
Time, (t)
Unre
liabili
ty,F
(t)
8/24/2004 09:43CALCE Center
WeibullLccc68 Sn/Ag
W2 RRX - SRM MEDF=16 / S=0Lccc68 Sn/Ag/Cu
W2 RRX - SRM MEDF=16 / S=0Lccc68 Sn/Pb
W2 RRX - SRM MEDF=15 / S=0Lccc84 Sn/Ag
W2 RRX - SRM MEDF=15 / S=0Lccc84 Sn/Ag/Cu
W2 RRX - SRM MEDF=16 / S=0Lccc84 Sn/Pb
W2 RRX - SRM MEDF=16 / S=0
At lower cyclicmean and maxtemperatures thePb-free soldersoutperformed SnPbsolder. This may berelated to the lowercreep rate of thePb-free soldersunder test ascompared to theSnPb solder.
SnPb
Pb-free
10 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Comparison of Time to Failure(68 IO Package)
For the Pb-free solders, increasing the average cyclic temperature showed adecrease in time to failure. As can be seen in the above chart, the behavior of theSnPb solder at the 100 and 125oC peak temperature shows non-monotonicallydecreasing behavior.
Peak Temperature (oC)(Dwell at Peak (min) )
Normalized
11 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
CALCE Strain Range Based Solder FatigueRapid Assessment Model
For eutectic solder,
• f Constant
•
1
1
2 2
cp
f
f
N
• Nf : mean number of cycles to failure
• p : inelastic strain range, g (package type,geometry, dimension, material property, load profile)
• K lead stiffness
• f model calibraton factor
• f = material constant, fatigue ductility coefficient
• c = material constant, fatigue ductility exponent, h(load profile)
• Tsj: mean cyclic temp. (°C)
• tD: dwell in minutes at the max. temp.
This model is preferred since it provides a physical relationship between thetemperature cycle load and failure and it has a quick solution time.
h
p
Ld
Ld (T) /2
Engelmaier, W., "Fatigue Life of Leadless Chip Carrier Solder Joints During Power Cycling,", Components,Hybrids, and Manufacturing Technology, IEEE Transactions on, Volume: 6 Issue: 3 , Sep 1983, pp. 232 -237
d
sjt
cTccc360
1ln210
Ah
TLfK dp
200
2
Leaded
Leadless
h
TfLdp
2
12 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Fitted Strain Range Model Parameters
2.253.472.25f*[1]
0.8980.9660.980R^2
1.40E-027.83E-031.45E-02c2
-2.10E-03-1.74E-03-7.34E-04c1
-0.416-0.347-0.502co
SASACSnPbSolder
Parameters
[1] The fatigue ductility constant was derived onlyconsidering the neutral distance length of thepackage. This value must be adjusted withrespect to the cyclic temperature range, CTEmismatch between the package and the board, andthe effective solder joint height.
d
sjt
cTccc360
1ln210
f = Constant
c
f
fe
TLN
1
]1[22
1
Norm
aliz
edF
atig
ue
Lif
eA Strain Range Based Model for Life Assessmentof Pb-free SAC Solder Interconnects , M. Osterman,A. Dasgupta, B. Han, 56th Electronic Component andTechnology Conference, pp. 884 - 890, May 30-June2, 2006 Dwell Time (hrs)
13 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
2 mm thick board contained PBGA,TSOP, TQFP, CLCC packages. Thesimulation model is based on testingconducted under the JGPP/JCAA Pb-free Solder Test Program.
Test assemblies were subjected to a-55 to 125oC temperature cycle and a-20 to 80oC cycle condition
calcePWA Model
•JCAA/JG-PP No-Lead Solder Project:-55ºC to +125ºC Thermal Cycle Testing Final Report, David Hillman and Ross Wilcoxon, March 15, 2006
Comparison with Stain Range SimulationModel
14 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Comparison of Simulation Results
Experiment Results
Sim
ula
tion
Results
TSOP (-20 to 80oC)
TQFP (-20 to 80oC)
Parts include (BGA,CLCC, TSOP, TQFP).Current model overestimates life of leadedparts. This result islikely due to the squareof T in estimating thestrain range for leadedparts.
•Data was obtained from
•JCAA/JG-PP No-Lead Solder Project:-55ºC to +125ºC Thermal Cycle Testing Final Report, David Hillman and Ross Wilcoxon, March 15, 2006
• Communication with T. Woodrow
15 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Leadless Strain Range for Leaded Parts
Experiment Cycles to Failure
Sim
ula
tion
Cyc
les
toF
ailu
re
TSOP and TQFPparts modeledwith the leadlessstrain rangemodel.
16 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Parts to bereworked
CALCE Thermal Aging and Rework Study- Test Board -
Board parameter• 8”x7”, single layer, one sided
(FR4) board• Board thickness: 62 mils• Parts to be reworked: 2 BGAs,
4 QFPs, 8 resistors (2512)• Glass transition temperature
(Tg): 130 ºC• Pb-free Board – ImSn Finish• SnPb Board – SnPb HASL
• Pb-free partsBGA (SAC305), QFP(Sn0.7Cu, Sn2Bi, Sn), 2512Resistors - (Sn)
• SnPb partsBGA (SnPb), QFP (SnPb),Resistor (SnPb)
Sn
Sn
SnCu
SnBi
Pb freePb-free Sn
Sn
SnBi
SnBiSnBi
SnCu
SnCu SnCu
Sn
Sn
Sn
Sn
Pb free Pb free
2512 resistors
17 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
SnPb Solder Joint Durability- BGA(Sn37Pb) – Sn37Pb Solder – HASL Pad
Finish -
1000.00 10000.001.00
5.00
10.00
50.00
90.00
99.00
Time (t) Hours
Unre
liab
ilit
y,F
(t)
WeibullSnPb- AgedW2 RRX - SRM MED
F=8 / S=0SnPb-Non agedW2 RRX - SRM MED
F=8 / S=0
=8.70, =1970, =0.95
=8.14, =2090, =0.97
Under a -40 to 125oC 1 hr cycle with 15 minute dwells, a decrease in life of5% was observed between aged (350hr/125oC) and non aged assemblies.
18 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Pb-free Solder Joint Durability- BGA (Sn3.0Ag0.5Cu) – Sn3.0Ag0.5Cu Solder – ImSn Pad
Finish
100.00 10000.001000.001.00
5.00
10.00
50.00
90.00
99.00
Time (t) Hours
Un
reli
abil
ity
,F
(t)
WeibullPb-free-AgedW2 RRX - SRM MED
F=7 / S=1Pb-free-Non agedW2 RRX - SRM MED
F=6 / S=2
=1.59, =1630, =0.97
=2.27, =2230, =0.93
Under a -40 to 125oC 1 hr cycle with 15 minute dwells, a decrease in life of25% was observed between aged (350hr/125oC) and non aged assemblies.
19 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Random Vibration Tests
A
C
B NM
D
E F
G H
I J
K L
O P
Q R
T U
V W
X Y
RNET1,2,3,4
RNET5,6,7,8
R1NET5,6,7,8
R1NET1,2,3,4
Step Stress Test Applied0.02 G2/Hz – 6 hrs0.05 G2/Hz – 6 hrs0.1 G2/Hz – 6 hrs0.2 G2/Hz – 18 hrs
Thermally aged (100 hr/125oC and350hr/125oC) conventional tin-leadassemblies (SnPb solder/HASL boardfinish) and lead-free (SAC305 solder/OSPboard finish) were subjected to a randomvibration stress step tests.
20 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Time To Failure Results Under Random VibrationAssembly comparison after 125C/100hrs aging
100
120
140
160
180
200
220
240
260
280
400 600 800 1000 1200 1400 1600 1800 2000
Strain (μe)
Tim
e-t
o-f
ailu
re
SnPb
OSP
Assembly comparison after 125C/350hrs aging
100
120
140
160
180
200
220
240
260
280
400 600 800 1000 1200 1400 1600 1800 2000
Strain (μe)
Tim
e-t
o-f
ailu
re
SnPb
OSP
At low strain levels,below approximately 700e SAC out lasts SnPb.The slow of SAC isshallower than SnPb.Both SAC and SnPbshow a degradation dueto thermal aging. Earlierfailures were ball gridarray parts.
21 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Test Setup: High Speed Flexure and Drop
Instrumented PWA with BGA
Test Specimen 4-Point Bend Fixture
22 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Failure Analysis: High Speed FlexureBulk solder failure
Component
Sn-Pb Solder
Sn-Pb Solder
Board
FR4 board failure
Failure site moves from bulk solderto intermetallic or copper trace asthe PWA flexure rate increases.
Board
Component
Sn-PbSolder
Copper
Intermetallic failure
BoardCopper trace failure
Sn-PbSolder
Sn-PbSolder
Board
Component
Cu-SnIntermetallic
Crack
Sn-Pb Solder
Copper
23 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
1E5
1E4
1E3PW
AS
train
(με)
1E0 1E1 1E2 1E3
SAC
Sn-Pb
Strain rate = 1E5 με/sec
Cycles to Failure (N)
Solder failure Cu trace failure
1E5
1E4
1E3PW
AS
train
(με)
1E0 1E1 1E2 1E3
SAC
Sn-Pb
Strain rate = 1E5 με/sec
Cycles to Failure (N)
Solder failure Cu trace failure
Un-aged Aged
Dynamic Durability: Sn37Pb vs SAC305
• PBGA-256 interconnects (1 mm pitch balls on OSP pads)• Dynamic 4-point bend test• Effect of thermal aging (100 hrs at 125o C)
• SnPb outperforms SAC• Failure modes include solder failure and Cu-trace failure• Aging reduces drop durability
24 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Electrochemical Migration Test Facilities
Control unit and data acquisition system
Temperature/humidity chamber
25 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
250 μm
Silver Migration on Lead-Free PCBDuring THB Testing
Sn-3.5Ag Solder onPolyimide Substrate withImmersion Sn Plating
EDS mapping revealed thatsilver migrated between thetwo electrodes. Sn-3.5Agwas the only source ofsilver in this sample.
26 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Flex crack
Printed circuitboard Solder pad
Capacitor termination
Solder joint
ElectrodeCeramic dielectric
Illustration of Flex Crack in MultilayerCeramic Capacitor (MLCC)
250 m
Flex crack
27 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Pb-Free Solder and MLCC Flex Cracking
Pb-free SolderMLCC parts weregenerally found tohave as good orbetter resistance toflex cracking ascompared to Sn37Pbsolder.
140 mm
Load span = 80 mm
Support span = 100 mm
85
mm
Strain on boardat 50% failure
(ε)
Strain on boardat 10% failure
(ε)
Strain on boardat 1% failure (ε)
Manuf.DielectricSizeSolder
18,6007,4003,300Vendor BX7R1812Sn3.0Ag0.5Cu
2,8001,9001,500Vendor BX7R1812Sn37Pb
4,8002,3001,700Vendor AX7R1812Sn3.0Ag0.5Cu
2,6001,7001,300Vendor AX7R1812Sn37Pb
28 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
http://www.calce.umd.edu/lead-free/tin-whiskers
CALCE Tin Whisker Study
In addition to conducting multiple research projects on lead free solder issues this past year, CALCEjoined with a number of companies to author an alert regarding the use of pure tin as a surface finish.
This alert was followed closely by a mitigation guide authored by CALCE with inputs fromcompanies participating in the Tin Whisker Alert Working Group.
29 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Effect of Reflow Temperatures on WhiskerFormation
Conflicting results have been presented on the impact ofexposure to solder reflow temperatures on whisker formation.
30 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Whisker Length and Growth AngleMeasurement
• Whisker length analysis (Best fit to lognormal distribution)
• Growth angle analysis– Angle growth demonstrates orientation preference. For this case, angle
distributed preferably in the range of 40 ~ 90
– Whisker growth angle appears to be independent of time
0
0.01
0.02
0.03
0.04
0.05
0 10 20 30 40 50 60 70 80 90
Length (µm)P
robab
ilit
y 8-month 13-month
18-month
13.0
50~60
11.4
40~50
6.7
30~40
18.1
60~70
7.9
20~30
15.420.54.32.8Percentage (%)
80~9070~8010~200~10Angle range ()
31 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
CALCE Tin Whisker Risk Assessment Software
A software package that calculates the probability of tin whiskerfailure for circuit card assemblies and products. Based on long-termtest data.
32 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
BGA(SnAgCu)
(Sn)
(Sn) (Sn)
(SnCu) (SnCu)
(SnCu)
(SnBi)
(SnBi) (SnBi)
QFP
FR4 board
CALCE Long-term Reliability of Mixed SolderStudy
Objectives:To provide participants with a critical assessment of the reliability of solderjoints formed with lead-free parts and Pb-based solder. This is particularly aconcern for companies that are attempting to maintain Pb-based solder.
Temperature Cycle Test Board
• Evaluations
– Intermetallics characterization underisothermal aging at 125ºC for 100,350 and 1000 hours
– Lead pull tests
– Thermal cycling (-40ºC to 125ºC)
– Vibration (step stress test)
33 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
Long-term Reliability of Pb-free ElectronicAssemblies in Contaminating Environments Study
Objective: To assess the long-term reliabilityof lead-free electronic assemblies subject tocontaminating and corroding environments.
CALCE Team: Sheng Zhan, Michael H. Azarian,Michael Osterman and Michael Pecht
Approach: Select board material and metalfinishes will be evaluated undertemperature/humidity/bias conditions withtest cells exposed to defined contaminationexposures as per Telecodia and surfaceinsulation resistance (SIR) will bemonitored.
Expected Benefits: Documented corrosionresistance measurements for a range of Pb-free materials and impact of contamination ofcorrosion based time to failure.
Electrochemicalmigration (ECM)failure site
Measured ECM Failure
34 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
FY07 CALCE Pb-Free ResearchC07-07 Solder Joint Reliability of Reworked/Repaired SMT AssembliesC07-01 Reliability of Pb-free and Reballed PBGAs in SnPb Assembly
ProcessC07-04 Solder Joint Reliability of Solder Dipped (SAC/SnPb) Leaded SMT
Packages in a SnPb Assembly ProcessC07-03 Effect of Long Dwell on Thermal Cycling Fatigue Damage for Pb-
Free Solders (Continuation of C06-03)C07-06 Effect of Temperature Cycle on the Durability Pb-free Interconnects
(Sn96.5Ag3.0Cu0.5 and SnCuNi) (continuation C06-06)C07-48 Characterization and Reliability Assessment of Lead-Free Solder
Alloys in High Temperature ApplicationsC07-02 Accelerated Qualification of SAC Assembly: Combined
Temperature Cycling & Vibration (Continuation of C06-02)C07-05 Tin Whisker Growth and Risk Assessment UpdateC07-08 Characterization of Tin Pest Formation in Pb-free Solder JointsC07-27 Characterization of PCB Laminate Materials Properties after Lead-
free Reflow CyclesC07-47 Acceleration factors in electrochemical migration
35 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
FY07 CALCE EPSC ResearchFailure MechanismsC07-10 Effect of solder fillet and composition factors on MLCC crackingC07-11 Reliability of Large Electrolytic CapacitorsC07-14 Electronic Component Failure Categorization under High G LoadingC07-34 Area Array Components Warpage Sensitivity
New Technologies and ProcessesC07-09 Hygroscopic Characterization of Polymer Materials beyond Glass
Transition TemperatureC07-12 Failure Mechanism & Reliability Assessment for System-in-Package
Technologies (Continuation of C06-12)C07-16 Detection of interconnect degradation using impedance analysisC07-17 Accelerated Testing of Flex AssembliesC07-18 Fundamental Understanding MEMs Structures Subjected to High Shock
LoadsC07-20 Qualification of a Stamped Metal Contact SocketC07-22 Measurement of Effective Chemical Shrinkage of Polymeric MaterialsC07-30 Characterization of Moisture-induced Degradation of Polymer InterfaceC07-31 Solder Assessment for SiC Device AttachmentC07-45 Power Cycling Durability of Advanced Power Modules
36 University of MarylandCopyright © 2007 CALCE
Center for Advanced Life Cycle Engineeringhttp://www.calce.umd.edu
FY07 CALCE EPSC Research
Part Management and SustainmentC07-23 Life Cycle Supply Chain Data Mining and InterpretationC07-24 Implementation Cost of Lead-Free and Tin Whisker Mitigation
Performance StandardsC07-25 Life Cycle Cost of Component Management: Understanding the
Component Reuse Business CaseC07-32 PoF Guidelines for Qualifying FPGAsC07-41 Counterfeit Electronic PartsThermal ManagementC07-26 Enhanced Conventional Thermal Solutions for LED PackagesC07-29 Thermal Performance and Reliability of Thermal Interface MaterialsVirtual QualificationC07-15 Shock –calcePWA Shock Model Improvements (continuation of C05-15)C07-21 Modeling Mechanical Torsion of PWA in calcePWAC07-28 Probabilistic PoF Modeling: Effect of Number of I/O on Thermal Cycling
Durability PredictionsC07-46 Model-based Design Guidelines for Shock & Drop Loading (Continuation
of C06-46)