MEASUREMENTS OF RESIDUAL STRESSES IN THIN FILMS DEPOSITED ON SILICON WAFERS BY INDENTATION FRACTURE

摘要

A semi-empirical formula is proposed to assess residual stresses in SiO_2 and Cr thin films depos- ited on Si wafers using Vickers indentation fracture tests. The formula indicates that the ratio of the inden- tation load to the cubic of square root of the crack length is linearly proportional to the reciprocal of the square root of the crack length, the magnitude of the residual stress, and the film thickness. Wafer curva- ture measurements are conducted to calibrate the dimensionless parameters in the proposed formula. The experimental results agree well with the theoretical prediction and the residual stresses in the SiO_2 and Cr thin films are evaluated to be -358 and 1095 MPa, respectively.