Method of appraising a dielectric film, method of calibrating temperature of a heat treatment device, and method of fabricating a semiconductor memory device

摘要

When tantalum pentoxide film that is deposited on silicon wafer is subjected to a heat treatment in an oxygen atmosphere to improve crystallinity, refractive index is measured by an ellipsometer to appraise change in the crystallinity or change in the relative dielectric constant of the dielectric film and judge the adequacy of the heat treatment temperature. In particular, when the dielectric film is a structure that includes tantalum pentoxide film in which crystallinity is changed by heat treatment and silicon oxide film in which film thickness is changed by heat treatment, the temperature of the heat treatment can be accurately appraised by taking advantage of the correlation between the temperatures of the heat treatment and the refractive indices of the laminated films, this correlation having a curve with a maximum point and a minimum point.