Method of making a SOI film having a more uniform thickness in a SOI substrate.

摘要

To provide a method of making a SOI film having a more uniform thickness in a SOI substrate which makes it possible to keep the variance at +/- 0.3 micrometers or less throughout the entire surface of the substrate, even for SOI substrates with a SOI film thickness between 1 micrometer and 10 micrometers. The surface of a SOI substrate is divided into a plurality of sections, then the SOI film thickness is measured for each section Wi (i = 1-n) by means of the spectral interference method using an optical fiber cable, and, simultaneously, the SOI film is etched down to a prescribed thickness by a dry etching device, and thus a desired value and a variance (+/- 0.3 micrometers) of the SOI film thickness is obtained.