Creep-fatique model for SAC405/305 solder joint reliability estimation—a proposal
Equation 1 Equation 2 Equation 3
reliability are shown in a Manson-
Solder Model Parameters
Coffin plot. The predictions are for an
accelerated test with a cyclic dwell time of
e
f
null c
0
c
1
c
2
t
0
10 minutes and a product operational cycle
Engelmaier-Wild Creep-Fatigue Model for SnPb Solders
with a dwell time of 600 minutes. In all
cases the cyclic mean temperature is 50°C.
SnPb 0.325 0.442 6.00e-04 -1.74e-02 360
As indicated in Table 1, there is not
Engelmaier Creep-Fatigue Model for Pb-Free Solders
as yet enough information for other SAC
from property data & accelerated test results
solders as well as SnAg to propose model
parameters. It is expected that the curves
SAC405/305 0.240 0.390 9.30e-04 -1.92e-02 100
for product reliability of SAC solders with
SAC205 <0.240 ? ? ? 100
lower Ag-content will lie below the curve for
SAC405/305; for solders containing Bi and
SAC105 <0.240 ? ? ? 100
In, the reliability will be better. SnAg <0.325 ? ? ? ~60
For ‘mixed’ SnPb/SAC solder joints,
the reliability will depend on whether the
Table 1. Model parameters for various solders.
peak reflow temperature was high enough
and of sufficient duration to achieve
uniform mixing and distribution. If that has
been achieved, the reliability will be about
the same as the SAC solder.
References
1. Engelmaier, W., “How to Estimate
Solder Joint Reliability, Part 1,” Global
SMT & Packaging, Vol. 7, No. 9, Sep-
tember 2007, pp. 60-64.
2. Engelmaier, W., “How to Estimate
Solder Joint Reliability, Part 2,” Global
SMT & Packaging, Vol. 7, No. 10,
October 2007, pp. 64-66.
3. Engelmaier, W., “Wear-Out System
Reliability with Multiple Components
and Load Levels,” Global SMT &
Figure 9— Manson-Coffin plot of SnPb and SAC solder joint accelerated creep-fatigue test results with model
Packaging, Vol. 8, No. 7, July 2008, pp.
predictions for accelerated tests with 10 minute dwells and product operation with 600 minute dwells with a
30-39.
mean cyclic temperature of 50°C for both.
4. Engelmaier, W., “Reliability of Lead-
Free (LF) Solder Joints,” Global SMT
Final Report, March 15, 2006. conferences, visit
www.ipc.org.
& Packaging, Vol. 3, No. 3, April
10. Osterman, M., A. Dasgupta and B. Werner Engelmaier has over 42 years
2003, pp. 36-38.
Han, “A Strain Range Based Model for experience in electronic packaging and intercon-
5. Engelmaier, W., “Reliability of Lead-
Life Assessment of Pb-free SAC Solder nection technology and has published over 180
Free (LF) Solder Joints Revisited,”
Interconnects,” Proc. 56th ECTC, papers, columns, book chapters and White
Global SMT & Packaging, Vol. 3, No.
May-June 2006, pp. 884-890. Papers. Known as ‘Mr. Reliability’ in the indus-
7, October 2003, pp. 26-27.
11. Engelmaier, W. in IPC-D-279, Design try, he is the president of Engelmaier Associates,
6. Engelmaier, W., “Achieving Solder
Guidelines for Reliable Surface Mount L.C., a firm providing consulting services on
Joint Reliability in A Lead-Free World,
Technology Printed Board Assemblies. reliability, manufacturing and processing aspects
Part 1,” Global SMT & Packaging, Vol.
IPC—Association Connecting Electron- of electronic packaging and interconnection
3, No. 6, June 2007, pp. 40-42.
ics Industries, July 1996. technology. He is the chairman of the IPC
7. Engelmaier, W., “Achieving Solder
Main Committee on Product Reliability. He
Joint Reliability in a Lead-Free World,
Werner Engelmaier will be giving some of his was elected into the IPC Hall of Fame 2003,
Part 2,” Global SMT & Packaging, Vol.
solder joint reliability and PCB reliability and was awarded the IPC President’s Award
7, No. 8, August 2007, pp. 44-46.
workshops at the IPC/JEDEC Conference in 1996 and the IEPS Electronic Packaging
8. Engelmaier, W., “Update on Lead-Free
on Transitioning to Lead-Free—Strategies for Achievement Award in 1987. He also was
Solder Joint Reliability,” Global SMT
Implementation, December 8-10, 2008 in named a Bell Telephone Laboratories Distin-
& Packaging, Vol. 8, No. 8, August
Dallas, TX, and the IPC EXPO/APEX guished Member of Technical Staff in 1986 and
2008, pp. 46-49.
Conference, March 28- April 2, 2009 in Las an IMAPS Fellow in 1996. More information
9. Hillman, D., and R. Wilcoxon, “-55ºC
Vegas, NV. For details on the workshops go to is available at
www.engelmaier.com, and he can
to +125ºC Thermal Cycle Testing,”
www.engelmaier.com; for information about the be reached at
engelmaier@aol.com.
JCAA/JG-PP No-Lead Solder Project,
48 – Global SMT & Packaging – December 2008
www.globalsmt.net
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