US 2001/0036714 A1 · Method of manufacturing semiconductor device

Abstract

Both P type and N type impurities are implanted from a plurality of directions. The tilt angle θ of the implantation direction against the normal of the main surface of a semiconductor substrate is fixed to 10°, and the deflection angle φ is set to such four directions (X, X+90°, X+180°, and X+270°, where X is an arbitrary angle) that projecting components of a vector indicating the implantation direction are opposed to each other on two lines that cross each other at right angles along the main surface of the semiconductor substrate. Thereby, the dependency of the breakdown voltage of element isolation on the direction of a well boundary is suppressed to realize a high breakdown voltage of element isolation in all directions.

Claims12

Dependent claims

A method of manufacturing a semiconductor device comprising the steps of:

(a) preparing a semiconductor substrate having a main surface;
(b) with M (M≧2) implantation types defined by combination of an impurity element and its implantation energy, performing an impurity implantation to said main surface through a plurality of shields disposed on said main surface, thereby to selectively form a P well and an N well adjacent each other in said main surface, and, for N (1≦N≦M) types of said M implantation types, performing said implantation from a plurality of directions such that projecting components of a vector indicating an implantation direction toward said main surface are cancelled with each other;
and
(c) forming a semiconductor element in each of said P well and said N well.

1 more element

Dependencies are inferred from the claim text.

Method of manufacturing semiconductor device

Life of this patent

Method of manufacturing semiconductor device

Life of this patent

Abstract

Claims12