Update on lead-free solder joint reliability
Werner Engelmaier
“It has been 2 years since the infamous ban of Pb-solders under RoHS. What have we learned? For solder
joints, no dramatic differences in reliability are apparent. The data bases for LF-solders have grown, the favored
LF-solders might be shifting, and no reliability model exists as of yet. Nevertheless, progress has been made.”
Update on lead-free
solder joint reliability
The reliability of lead-free solder joints
Fig. 1
Nothing much has changed in finding of 0 100°C to –65 +150°C with
has been addressed in previous Global the results of accelerated testing of SAC dwells of 10 to 60 minutes and mean
SMT & Packaging columns
1-5
to the extent solders confusing and compa
ri
sons with fatigue lives of 16 to 8,200 cycles-to-
possible at that time. When I started this90 SnPb solder contradictory. In Figures 1 failure, predominately SAC 305 and
column, it was meant as a one-part issue, through 13, a representative
75
sample of SAC405, but also SAC105, SAC205 and
but it grew so much it needed to be split published accelerated test results is given. SAC-solders with Ni, Bi, and Zn, as well
50
into two parts. The data range from temperature cycles as ‘mixed’ SAC/SnPb.
Fig. 1Fig. 1
Fig. 3
25
% Failed
10
CSP Components on FR-4, 5 mm
QFN w/3.45 mm
Die
90 90 ATC: per IPC-9701 Package on FR-4,
75 75
ATC: per IPC-9701
5
-55 +125°C, 10°C/min ramps,
10 minute dwells @ -55°C & 0 100°C, 10°C/min ramps,
10 minute dwells
50 50
30 minute dwells @ +125°C
Sn37Pb
2
Sn37Pb
SAC 405
SAC 305
25 25
1
10
2
200 500 10
3
2,000 5,000 10
4
% Failed % Failed
Cycles-to-Failure
1
10 10
CSP Components on FR-4, CSP Components on FR-4,
ATC: per IPC-9701 ATC: per IPC-9701
5 5
-55 +125°C, 10°C/min ramps, -55 +125°C, 10°C/min ramps,
10 minute dwells @ -55°C & 10 minute dwells @ -55°C &
30 minute dwells @ +125°C 30 minute dwells @ +125°C
Fig. 1
2 2
Sn37Pb Sn37Pb
SAC 405 SAC 405
1 1
Fig. 1
10
2
10
2
200 200 500 50010
3
10
3
2,000 2,000 5,000 5,00010
4
10
4
Cycles-to-FailureCycles-to-Failure
1 1 3
90
75
90
Fig
ure 1. Weibull plots of Sn37Pb and SAC405
75
Figure 3. Weibull plots of Sn37Pb and SAC305 [Source: Alex Chan, Alcatel-Lucent,
50
[Source: Dave Hillman, Rockwell Collins, USA]. Canada, Aman Khan, Int. Rectifier, USA, and Robert Kinvaniui, Samina-SCI, USA].
Fig. 2
50
Fig. 4
25
25
% Failed
9 mm
QFN w/7.14 mm
Die
10
CSP Components on FR-4,
7 mm
QFN w/5.16 mm
ATC: per IPC-9701
90
Package on FR-4, % Failed
10
CSP
90
Components on FR-4, Die Package on FR-4,
ATC: per IPC-9701
5
-55 +125°C, 10°C/min ramps, ATC: per IPC-9701
75
ATC: per IPC-9701
10 minute dwells @ -55°C & 0 100°C, 10°C/min ramps,
75
10 minute dwells
5
-55 +125°C, 10°C/min ramps, 0 100°C,
30 minute dwells @ +125°C 10 minute dwells @ -55°C &
10°C/min ramps,
2
50
Sn37Pb Sn37Pb
50
30 minute dwells @ +125°C
SAC 305
10 minute dwells
SAC 405
2
Sn37Pb Sn37Pb
1
25
25
SAC 405 SAC 305
10
2
200 500 10
3
2,000 5,000
10
4
1
Cycles-to-Failure
1
% Failed
10
2
200 500 10
3
2,000 5,000 10
4
10
Cycles-to-Failure
% Failed 1
10
5
5
2
2
1 1
10
2
200 500 10
3
2,000 5,000 10
4
10
2
200 500 10
3
2,000 5,000 10
4
Cycles-to-Failure
2
Cycles-to-Failure
4
Figure 2. Weibull plots of Sn37Pb and SAC305 [Source: Alex Chan, Alcatel-Lucent, Figure 4. Weibull plots of Sn37Pb and SAC305 [Source: Alex Chan, Alcatel-Lucent,
Canada, Aman Khan, Int. Rectifier, USA, and Robert Kinvaniui, Sanmina-SCI, USA]. Canada, Aman Khan, Int. Rectifier, USA, and Robert Kinvaniui, Samina-SCI, USA].
46 – Global SMT & Packaging - August 2008
www.globalsmt.net
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