STRUCTURE OF SEMICONDUCTOR SUBSTRATE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To realize a method for forming a trench which can restrain increase of working conversion error of lithography and relieve electric field concentration in an upper edge. SOLUTION: The trench 3 is formed by etching a main surface 2 having a (100) face of a silicon substrate 1. By wet treatment using mixed solution of HF and ozone water, a (111) face of the silicon substrate is etched selectively, and configuration of the upper edge of the trench 3 is shaped.