Development of scanning type infrared laser photoelasticity and evaluation of residual stress in {100} GaAs wafers

摘要

We developed an optical birefring ence measure-ment method that uses a photoelastic modulator and a polarized laser. A He-Ne infrared laser was utilized as the light source for measuring the birefringence in gallium arsenide wafers. In this paper we will explain the theory of this method and the process of measuring the stress in GaAs wafers. The magnitude of the principal stess deviation as well as the directions of the principal stresses were obtained simultaneously with a high resolution power. The optical biefringences of three different qualities of GaAs wafers were measured. From the experimental results, it was found that the residual stress of GaAs wafers can be obtained using our measurement.