The Effect of High Dissipation Components on the Solder Joints of Ceramic Chip Carriers Attached to Thick Film Alumina Substrates

The effects of power cycling and powered high temperature storage on chip carriers solder attached to thick film alumina substrates are compared with those of conventional temperature cycling and high temperature storage. Although the high temperature storage tests gave a similar deterioration in torque strength compared with unstressed controls, power cycling produced dramatically lower values than chamber temperature cycling with the same upper ternperature. The power cycling failure mechanism is seen to be a direct result of the thermal gradient changes between the chip carrier and the substrate resulting in plastic deformation and subsequent fatigue cracking. Possible solutions to the problem are reviewed.