Testing of properties for soldered leadless chip carrier assemblies

Sample preparation, techniques and fixtures for measuring the yield strength and electrical resistance of soldered leadless chip carriers are discussed and test results are summarized. It is shown that the yield strength of leadless hermetic packages soldered to thick film metallization is substantially that of the solder (5000 lbf/sq in.), which makes these devices strong enough for current applications. The results also demonstrate to what extent stress testing affects the resistance and shear strength of the joints and indicate the magnitude of the effects of the various processing and environmental conditions on the integrity of soldered chip carrier assemblies.