JPS57100734A - Etching method for semiconductor substrate - Google Patents

Abstract

PURPOSE:To form recess regions of different depth on the same substrate by utilizing the difference of etching rate between the substrate and the mask with the etchant. CONSTITUTION:A silicon dioxide film 2 is formed on a silicon substrate 1, the silicon dioxide film of shallow recess region is removed, the silicon dioxide film 4 is formed in a thickness of 600mum at the part 3, a region 5 removed with the silicon dioxide film of the deep recess region is formed by etching, the substrate 1 and the silicon dioxide becoming mask materials start etching with an etchant for simultaneously etching both, the etching is continued until the film 4 of shallow recess region is removed, the depth of the deep region becomes 25mum, the etching is further proceeded, and is stopped when the depth of the shallow region 8 becomes 15mum, and then the depth of the deep recess region 6 becomes 40mum.