US 5,346,841 AGranted

Method of manufacturing semiconductor device using ion implantation

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorKotaro Yajima

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Abstract

In a method of manufacturing a semiconductor device, after forming a mask for blocking ion implantation in a predetermined position on the main surface of a silicon substrate, oxygen ions are implanted from the direction making an angle of about 45.degree. with respect to the main surface while intermittently changing the implantation energy and the dose in a suitable manner. This process of oxygen ion implantation is carried out with the silicon substrate being rotated in a plane parallel to the surface. According to the process above, an element isolation film is formed surrounding a portion below an active region in the silicon substrate only by the process of oxygen ion implantation and a heat treatment process after that. As a result, the productivity is increased compared with in the conventional method in which an element isolation film on the side portion of the active region is formed by thermal oxidation, and degradation of the properties of crystal and residual ions in the active regions are also prevented.

Claims3

Dependent claims

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

preparing a semiconductor substrate formed of single crystal silicon;
forming a mask for block ion implantation on the main surface of the semiconductor substrate;
and
implanting oxygen ions from the direction making an angle of about 45.degree. with respect to the main surface of said semiconductor substrate while intermittently changing values of the implantation energy and the dose to form an insulator layer including oxide silicon surrounding an active region in said semiconductor substrate, increasing the values of the ion implantation energy being accompanied with increasing the values of the dose, the values of the implantation energy and the dose being selected so as to fully enclose said active region with said insulator layer,
wherein said step of the irradiation of the oxygen ions is carried out with said semiconductor substrate being rotated in a plane parallel to the main surface, and
said step of forming the mask includes the steps of depositing a silicon oxide film on the main surface on said semiconductor substrate, selectively removing this silicon oxide film to form a patterned silicon oxide film, and then further covering the surface and side surface of the patterned silicon oxide film with a silicon nitride film.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/086,741Filed 6 Jul 1993 · continuation
Priority: JP 2-22205321 Aug 1990
Granted: 13 Sep 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

H10P 30/209
Of electrically inactive species: in silicon to make buried insulating layers
H10P 30/221
Using masks: characterised by the angle between the ion beam and the mask
H10P 30/222
Into semiconductor materials, e.g. for doping: characterised by the angle between the ion beam and the crystal planes or the main crystal surface
H10P 90/1906
Preparing vertically inhomogeneous wafers: preparing SOI wafers

Family

Serial744,107Parent of this continuation · filed 13 Aug 1991
US 5,346,841 AThis patent

From the US filing history. Foreign family members aren’t listed.

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