A testing method and device for intrinsic stress measurement in wafer bumping process

A novel concept and the related testing methodology of a sensing device is presented. This device is used to determine the local intrinsic stresses induced in wafer processes such as metallization and bumping. The sensing device is essentially a pressure sensor structure with a specified membrane thickness. This sensing wafer is put into the processes which are under investigation and is processed together with the production wafers. During the process, the membrane is deformed due to the process induced intrinsic stress. The membrane deformation is either monitored continuously or measured after each process step by an optical method. Intrinsic stresses are calculated from the measured membrane deformations.