# US 5,352,626 A · Method for making a semiconductor device having an isolated layer region on the side wall of a groove

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,352,626 A
- Document ID: US5352626A
- Status: Granted
- Kind: A
- Application number: 08/153,906
- Filed: 1993-11-17
- Granted: 1994-10-04
- Earliest claimed: 1990-04-09
- Assignees: Seiko Instruments Inc.
- Inventors: Takashi Hosaka
- Web page: https://patentgrep.com/patent/US5352626A

## CPC

- H10W 10/012: {using local oxidation of silicon [LOCOS]}
- H10W 10/13: formed using local oxidation of silicon [LOCOS], e.g. sealed interface localised oxidation [SILO] or side-wall mask isolation [SWAMI]
- Y10S 148/117: Oxidation, selective
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Steps or grooves are formed in a surface of a semiconductor substrate of a semiconductor device having a plurality of semiconductor elements, and an isolation Layer is formed on regions that include the steps or side walls of the grooves.

## Claims

### Claim 1

A method for making a semiconductor device in a semiconductor substrate having a surface, the device including an isolation layer region formed on a side wall of a groove provided in a portion of the surface of the semiconductor substrate and at least two separate active regions isolated from one another by the isolation layer region, said method comprising the steps of:
forming a pattern of photoresist on said semiconductor substrate surface such that a portion of the surface is exposed;
forming a groove in said substrate at the exposed portion so that the groove has side walls which form an angle with the substrate surface;
removing the photoresist, forming a thin insulation film on the substrate surface and in the groove, and depositing a silicon nitride film on the thin insulation film;
removing the silicon nitride film from the side walls of the groove thereby leaving remaining portions of the silicon nitride film;
forming an inversion protection layer by introducing impurities into the side walls from which the silicon nitride film has been removed;
forming insulation films constituting isolation layer regions on the side walls from which the silicon nitride film has been removed by oxidizing said semiconductor substrate;
removing the remaining portions of the silicon nitride film and the thin insulating film; and
forming impurity diffusion regions constituting separate active regions in portions of the substrate separated by an isolation layer region.

### Claim 2 (depends on 1)

A method as defined in claim 1 wherein said step of forming impurity diffusion regions comprises: forming a thin insulating film on the portions of the substrate separated by an isolation layer region; and ion implanting impurities through the thin insulating film.