Solder assembly of cantilever bar force or displacement sensors

In this paper, the stability of a displacement sensor assembled with Sn96 (tin- silver) solder, Sn62 (tin-leadsilver) solder or conductive silver-loaded epoxy glue was compared. In the absence of humidity or thermal cycling, the glue was found to be much better than both solders. This is ascribed to better creep behaviour combined with lower elastic modulus and much smaller bond thickness. However, the glue underwent severe degradation in hot, humid air, and is therefore not suitable for all applications. Among the solder alloys, high temperature Sn96 exhibited higher stability than the standard Sn62, in accordance with expectations.