Method for making mask aligned narrow isolation grooves for a semiconductor device

摘要

A method for making mask aligned narrow isolation grooves for a semiconductor device in which an insulating layer is filled in a groove of the semiconductor substrate to form an island region surrounded by the insulating layer, which comprises the steps of forming a mask pattern on a major surface of the semiconductor substrate in such a manner that its side wall is at a taper angle of 90 DEG or less with respect to a major surface of the semiconductor substrate; ion-implanting an impurity of a conductivity type opposite to that of the semiconductor substrate into the semiconductor substrate using the mask pattern; causing a groove for the insulating material to be formed in the semiconductor substrate around the side wall of the mask pattern; filling the groove with insulating material to form a narrow insulating layer; and diffusing the implanted impurity to form an isolation region surrounded by the insulating material.