Reduction of thermomechanical stress by applying a low temperature joining technique

Schwarzbauer and Kuhnert proposed a novel low temperature joining (LTJ) technique to connect silicon wafers with molybdenum backplates [1989, 1991]. Investigation of the bond build-up led to the idea to influence the thermomechanical stresses between bonded materials. By measuring the temperature dependent bow of silicon disks of 26 mm diameter joined to molybdenum backplates the stresses inside both materials were determined. The experiments revealed that variation of process parameters allows one to control the temperature at which no stress occurs between the joined disks. This can be used to considerably reduce thermomechanical stress caused by temperature cycling.