On-wafer heating tests to study stability of silicon devices
A new on-wafer heating test structure is proposed for wafer level stability testing. The test structure is based on Wheatstone bridge configuration. Two out of four resistors are covered by aluminum. An optimization of the on-wafer heating technique is presented. The new structure and the structure consisting of two out of four resistors with the large openings in the silicon dioxide/nitride layers are measured. The piezoresitance effect was utilized to measure the mechanical stress in the silicon substrate. The mechanical stress is induced during the device fabrication. The effect of aluminum and silicon dioxide/nitride layers on the device stability was studied. A strong influence of aluminum layers on silicon device stability was observed.