Method of forming SOI substrate which includes forming trenches during etching of top semiconductor layer

Abstract

The present invention provides a method of forming SOI substrate provided with an isolation layer. Since a thinning process is performed at the semiconductor silicon layer after isolation layers are formed on the semiconductor silicon layer, the occurrence of dishing is prevented. The method of forming SOI substrate according to the present invention comprises the steps of: providing a base silicon layer and a semiconductor silicon layer; forming a buried oxide layer on the base silicon layer; forming trenches in the semiconductor silicon layer; boding the base silicon layer and the semiconductor silicon layer so that the buried oxide layer and the trench-formed surface are contacted with each other; removing a selected thickness of the semiconductor silicon layer to obtain a semiconductor layer having a desired thickness, wherein the trenches formed in the semiconductor silicon layer are exposed by removing the selected thickness of the semiconductor silicon layer and the semiconductor layer is separated into a plurality of regions by the exposed trenches; forming an etch stop layer only on the semiconductor layer except the trenches; forming an oxide layer with a thickness sufficient to fill a region between stacked structures comprising the semiconductor layer and the etch stop layer; etching the oxide layer by means of the etch stop layer, wherein an isolation layer is formed at the region between the stacked structure; and removing the etch stop layer.

Dependencies are inferred from the claim text.