Nondestructive measurement of in plane residual stresses in thin silicon substrates by infrared transmission

This paper describes an optical infrared transmission technique to measure the in plane residual stresses in thin single crystal silicon substrates. F ringe multiplication and phase stepping are incorporated to increase the se nsitivity of the stress measurement. The measurement is full field and nonc ontact, and the data processing is automatic. When the fringe multiplicatio n factor of 11 is employed, the measurement sensitivity of the maximum resi dual shear stress can be 0.4 MPa (58 psi). Both (100) and (111) silicon sam ples were investigated with this method.