Development of Auto Infrared Photoelastic Microscope for Stress Measurement of Silicon

Silicon based materials take a great importance in semiconductor and electronics industries. Detecting the cracks and measuring the stress have become increasingly important for electronic packaging. With knowing of the position and the range of stress concentration and crack zone, people can optimize the arrangement before manufacturing or detect the reliability of devices inworking. We introduce an instrument in this paper which is used to measure both stresses and cracks in silicon based materials for electronic packaging. The instrument was built as a microscope (maximum multiple 20) based on infrared photo elasticity. It was built with the function of automatic rotation of optical devices inside the instrument instead the traditional manual rotation which greatly improved the resolution and stability. A micro heating platform (500 °Cmax) can be attached for some experiments with temperature requirement such as TSV temperature cycling test. The resolution of stress-birefringence phase difference is less than 2° (calibrated by the quarter wave plate). It can also be used in Si or SiC wafer bonding quality detection, and stress in MEMS can be measured as well.