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| EPSI INC. - Electronics Packaging Solutions International Inc. Contact us at: P.O. Box 1522, Montclair, NJ 07042 USA, tel.: +1 (973)746-3796, fax: +1 (973)655-0815 e-mail: jpclech@aol.com |
DECEMBER 2003
"Lead-Free and Mixed Assembly Solder Joint Reliability Trends", by J-P. Clech. Paper to be presented during the
IPC/SMEMA Council APEX 2004 Conference, Anaheim, CA, February 21-26, 2004.
Abstract:
"This paper presents a quantitative analysis of solder joint reliability data for lead-free Sn-Ag-Cu (SAC) and mixed assembly
(SnPb + SAC) circuit boards based on an extensive, but non-exhaustive, collection of thermal cycling test results. The
assembled database covers life test results under multiple test conditions and for a variety of components: conventional SMT
(LCCCs, resistors), Ball Grid Arrays, Chip Scale Packages (CSPs), wafer-level CSPs, and flip-chip assemblies with and
without underfill. First-order life correlations are developed for SAC assemblies under thermal cycling conditions. The results
of this analysis are put in perspective with the correlation of life test results for SnPb control assemblies. Fatigue life
correlations show different slopes for SAC versus SnPb assemblies, suggesting opposite reliability trends under low or high
stress conditions. The paper also presents an analysis of the effect of Pb contamination and board finish on lead-free solder
joint reliability. Last, test data are presented to compare the life of mixed solder assemblies to that of standard SnPb
assemblies for a wide variety of area-array components. The trend analysis compares the life of area-array assemblies with:
1) SAC balls and SAC or SnPb paste; 2) SnPb balls assembled with SAC or SnPb paste."
Pre-prints of this paper are available to customers of our lead-free reliability program upon request (e-mail to:
jpclech@aol.com).
NOVEMBER 2003
We recently completed a study and analysis of SnAgCu (SAC) steady-state creep data in shear, including the
development of first-order steady-state creep models for SAC joints in shear.
As part of our development work on lead-free solder constitutive models, we analyzed multi-sourced SAC shear creep data
in an attempt to consolidate creep measurements over a wide range of stress, temperature and strain rate conditions. Results
from several laboratories were found to be in good agreement. Differences were identified that were attributed to process or
ageing conditions. The study also investigated the effects of the SAC alloy composition, and a comparison of SAC creep
data in shear and tension as well as a comparison of creep data for SAC and Sn3.5Ag solder.
Results of this study will appear in Micromaterials & Nanomaterials, A Publication Series of the Micro Materials Center
Berlin (MMCB) at the Fraunhofer Institute for Reliability and Microintegration (IZM), Berlin, Germany, Issue No. 3, 2003,
Dr Andreas Schubert in memoriam.
Pre-prints of the report are available to customers involved in our lead-free reliability program.
OCTOBER 2003
New life test data correlations for flip-chip and TSOP assemblies with SnAgCu (SAC) or SnPb solder confirm
previously established trends showing the cross-over of SAC and SnPb fatigue curves.
We recently established correlations of TSOP and bare flip-chip thermal cycling test lives, using multi-sourced independent
test data. The results, shown as characteristic lives versus temperature swing or the applied cyclic shear strain, correlate as
trendlines with distinct slopes and cross-over points that separate "low" and "high" stress conditions. The implication is that,
even if SAC test results are worse than SnPb results under accelerated test conditions, SAC assemblies may still be as reliable
or more reliable than SnPb assemblies under mild-enough use conditions. However, reliability concerns remain for
applications in harsh environments.
The TSOP and flip-chip data analysis confirms similar SAC vs. SnPb trends we previously established for resistors and
area-array packages.
The above correlations, among other findings of our reliability investigations, will be presented in upcoming lead-free reliability
workshops (e.g.: at IPC/JEDEC 4th Lead-Free Conference, in-house or web-cast seminars...).
SEPTEMBER 2003
Lisa Hamburg, Editor-In-Chief, Circuits Assembly Magazine, and Jean-Paul Clech, EPSI Inc., received the
SMTA's 2003 Member of Distinction Awards during the SMTA International Conference in Chicago. This award
"honors a select group of individuals who have served the Association tirelessy" and "have made a lasting contribution
to the Association by sharing their time and expertise with the SMTA membership".
"Dr. Jean-Paul Clech was nominated to receive the Member of Distinction Award because of his long-standing
support of the SMTA. He has been a member of the Association since September 1995 and directly involved in
Technical, Bookstore and Journal Committees. The SMTA has benefited from his technical expertise in the way of
courses he has taught and conference papers he has presented. Also, he has been an asset in organizing programs
such as SMTA International and our regional events through his contacts in securing outstanding speakers.
Jean-Paul is one of the SMTA's "Experts" in getting answers to technical questions and concerns. He is never "too
busy" to carefully and completely explain solutions to issues addressed to him by members as well as the SMTA Staff.
The presentation of the SMTA Member of Distinction Award places Jean-Paul Clech among other award winners
with the honor he well deserves" .
"Lisa Hamburg, our second winner of the Member of Distinction Award has consistently demonstrated her support
for the industry through her editorials and advertising coverage in Circuits Assembly Magazine and involvement in
SMTA educational programs as well as leadership on the Chapter level.
As an active member and volunteer of the Atlanta chapter, she has served as Vice President, Vice President
Technical Programs, Chair of the Chapter Scholarship Fund and is an active member of the highly successful Atlanta
Expo. Her involvement with SMTA nationally includes chairing conference sessions, speaking at numerous chapters
and moderating a panel discussion, which received "rave reviews". She has worked hard to assist SMTA with the
Contract Manufacturing Symposium at SMTA International, participating as a member of the SMTA International
Technical Committee as well as the Hutchins Education Grant Committee.
The above contributions are some of the many seminal efforts that Lisa has contributed to the success of SMTA
nationally and locally. Considering Lisa's exceptional generosity and commitment to the SMTA, she was heartily
recommended to receive the SMTA Member of Distinction Award".
-- Excerpts from the 2003 SMTA Annual Meeting booklet (September 23, 2003, Chicago, IL).
For more information on the SMTA, visit http://www.smta.org .
"Lead-Free and Mixed Assembly Solder Joint Reliability Trends", by J-P. Clech. Paper to be presented during the
IPC/SMEMA Council APEX 2004 Conference, Anaheim, CA, February 21-26, 2004.
Abstract:
"This paper presents a quantitative analysis of solder joint reliability data for lead-free Sn-Ag-Cu (SAC) and mixed assembly
(SnPb + SAC) circuit boards based on an extensive, but non-exhaustive, collection of thermal cycling test results. The
assembled database covers life test results under multiple test conditions and for a variety of components: conventional SMT
(LCCCs, resistors), Ball Grid Arrays, Chip Scale Packages (CSPs), wafer-level CSPs, and flip-chip assemblies with and
without underfill. First-order life correlations are developed for SAC assemblies under thermal cycling conditions. The results
of this analysis are put in perspective with the correlation of life test results for SnPb control assemblies. Fatigue life
correlations show different slopes for SAC versus SnPb assemblies, suggesting opposite reliability trends under low or high
stress conditions. The paper also presents an analysis of the effect of Pb contamination and board finish on lead-free solder
joint reliability. Last, test data are presented to compare the life of mixed solder assemblies to that of standard SnPb
assemblies for a wide variety of area-array components. The trend analysis compares the life of area-array assemblies with:
1) SAC balls and SAC or SnPb paste; 2) SnPb balls assembled with SAC or SnPb paste."
Pre-prints of this paper are available to customers of our lead-free reliability program upon request (e-mail to:
jpclech@aol.com).
NOVEMBER 2003
We recently completed a study and analysis of SnAgCu (SAC) steady-state creep data in shear, including the
development of first-order steady-state creep models for SAC joints in shear.
As part of our development work on lead-free solder constitutive models, we analyzed multi-sourced SAC shear creep data
in an attempt to consolidate creep measurements over a wide range of stress, temperature and strain rate conditions. Results
from several laboratories were found to be in good agreement. Differences were identified that were attributed to process or
ageing conditions. The study also investigated the effects of the SAC alloy composition, and a comparison of SAC creep
data in shear and tension as well as a comparison of creep data for SAC and Sn3.5Ag solder.
Results of this study will appear in Micromaterials & Nanomaterials, A Publication Series of the Micro Materials Center
Berlin (MMCB) at the Fraunhofer Institute for Reliability and Microintegration (IZM), Berlin, Germany, Issue No. 3, 2003,
Dr Andreas Schubert in memoriam.
Pre-prints of the report are available to customers involved in our lead-free reliability program.
OCTOBER 2003
New life test data correlations for flip-chip and TSOP assemblies with SnAgCu (SAC) or SnPb solder confirm
previously established trends showing the cross-over of SAC and SnPb fatigue curves.
We recently established correlations of TSOP and bare flip-chip thermal cycling test lives, using multi-sourced independent
test data. The results, shown as characteristic lives versus temperature swing or the applied cyclic shear strain, correlate as
trendlines with distinct slopes and cross-over points that separate "low" and "high" stress conditions. The implication is that,
even if SAC test results are worse than SnPb results under accelerated test conditions, SAC assemblies may still be as reliable
or more reliable than SnPb assemblies under mild-enough use conditions. However, reliability concerns remain for
applications in harsh environments.
The TSOP and flip-chip data analysis confirms similar SAC vs. SnPb trends we previously established for resistors and
area-array packages.
The above correlations, among other findings of our reliability investigations, will be presented in upcoming lead-free reliability
workshops (e.g.: at IPC/JEDEC 4th Lead-Free Conference, in-house or web-cast seminars...).
SEPTEMBER 2003
Lisa Hamburg, Editor-In-Chief, Circuits Assembly Magazine, and Jean-Paul Clech, EPSI Inc., received the
SMTA's 2003 Member of Distinction Awards during the SMTA International Conference in Chicago. This award
"honors a select group of individuals who have served the Association tirelessy" and "have made a lasting contribution
to the Association by sharing their time and expertise with the SMTA membership".
"Dr. Jean-Paul Clech was nominated to receive the Member of Distinction Award because of his long-standing
support of the SMTA. He has been a member of the Association since September 1995 and directly involved in
Technical, Bookstore and Journal Committees. The SMTA has benefited from his technical expertise in the way of
courses he has taught and conference papers he has presented. Also, he has been an asset in organizing programs
such as SMTA International and our regional events through his contacts in securing outstanding speakers.
Jean-Paul is one of the SMTA's "Experts" in getting answers to technical questions and concerns. He is never "too
busy" to carefully and completely explain solutions to issues addressed to him by members as well as the SMTA Staff.
The presentation of the SMTA Member of Distinction Award places Jean-Paul Clech among other award winners
with the honor he well deserves" .
"Lisa Hamburg, our second winner of the Member of Distinction Award has consistently demonstrated her support
for the industry through her editorials and advertising coverage in Circuits Assembly Magazine and involvement in
SMTA educational programs as well as leadership on the Chapter level.
As an active member and volunteer of the Atlanta chapter, she has served as Vice President, Vice President
Technical Programs, Chair of the Chapter Scholarship Fund and is an active member of the highly successful Atlanta
Expo. Her involvement with SMTA nationally includes chairing conference sessions, speaking at numerous chapters
and moderating a panel discussion, which received "rave reviews". She has worked hard to assist SMTA with the
Contract Manufacturing Symposium at SMTA International, participating as a member of the SMTA International
Technical Committee as well as the Hutchins Education Grant Committee.
The above contributions are some of the many seminal efforts that Lisa has contributed to the success of SMTA
nationally and locally. Considering Lisa's exceptional generosity and commitment to the SMTA, she was heartily
recommended to receive the SMTA Member of Distinction Award".
-- Excerpts from the 2003 SMTA Annual Meeting booklet (September 23, 2003, Chicago, IL).
For more information on the SMTA, visit http://www.smta.org .