31 4 August, 2015
Alternative Solders II
Zn-based Alloys
New formulations demonstrate lower mechanical stress and reduced die cracking
Growth of brittle intermetallics at high temperature limits reliability
Improved reliability expected for die<10mm^2 in combination with a new experimental lf
surface
Risk of Zn re-deposition can only be falsified in high-volume manufacturing
Material currently only available in wire form
Bi-based Alloys
Low thermal conductivity & low melting point
Performance minor to high lead solder no replacement option
SnSb-based Alloys
New formulations demonstrate acceptable melting point
Workability to be improved (voiding, die cracking)
Limited surface compatibility (chip backside, leadframe finish)
Reliability not yet demonstrated
Material currently only available in paste form