SAC105+Mn (SACM)
- First RELIABLE low-Ag solder alloy
- Thermal Cycling: Comparable to SAC305
- Drop Testing: Significantly better than SAC305
- Available for licensing in China
- SuperFlex is the 1st licensee
- Lead-free with low environmental impact
- Reduces the silver content and price volatility
- Drop shock reliability better than SAC105 for hand held device market
- Thermal reliability characteristics comparable to, and in some cases better than, standard high cost, high silver solder alloys
- Manufacturing yield comparable to SAC305
- Only very small adjustments needed for soldering process
- Compatible with high-silver, low-silver, or no-silver alloys used in wave soldering and hand soldering
- Selling in high volume to Chinese licensees
Work Performed by Dr. Ning-Cheng Lee and his team on SACM
SACM: 98.5Sn/1Ag/0.5Cu/0.05Mn
JEDEC Drop Test (JDT)
250 thermal cycles for aging
Characteristic Life (50% fails) in Drop Test
SACM>SnPb>SAC105>SAC305
Thermal Cycle Test
(-40 to 125°C)
Characteristic Life TCT
SACM>SAC305>SAC105>SnPb
Conclusions
SACM has better drop shock performance than SAC105 and much better drop shock performance than SAC305.
SACM matches SAC305 in thermal cycle performance.
Hence, SACM is a better choice than SAC105 or SAC305.
The mechanism for the improved performance is attributed to a stabilized microstructure with a uniform distribution of IMC particles.
Technical Papers
Achieving High Reliability Low Cost SAC Solder Joints via Mn or Ce Doping (English)
通过Mn或Ce 掺杂技术获得可靠程度高，成本低的无铅SAC焊 (Chinese)
A Brief History of SAC Alloys
Circa 1999: Near eutectic SAC387 is initial lead-free alloy of choice
- Eutectic is alloy of choice as it is replacing eutectic SnPb
- 100s millions of mobile phones assembled with this alloy to date
SAC305 becomes IPC’s Solder Products Value Council's "Alloy of Choice" ~2006
- Exhibits less tombstoning than SAC387
- Uses less silver
SAC105 achieves wide acceptance around 2007-2008 to now
- Less silver
- Performs better in drop shock than SAC305, but worse in thermal cycle (TC)
- Disadvantage: Tm is 225°C vs. SAC305 219°C
