# US 5,705,027 A · Method of removing etching residues

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- Number: US 5,705,027 A
- Document ID: US5705027A
- Status: Granted
- Kind: A
- Application number: 08/551,597
- Filed: 1995-11-01
- Granted: 1998-01-06
- Earliest claimed: 1995-04-18
- Assignees: Mitsubishi Denki Kabushiki Kaisha
- Inventors: Toshiharu Katayama; Naoko Ootani
- Web page: https://patentgrep.com/patent/US5705027A

## CPC

- C25F 3/12: of semiconducting materials
- H10P 50/613: {of Group IV materials}
- Y10S 438/911: Differential oxidation and etching
- C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The method is to selectively etch the etching residue in non-conductive state occurring in semiconductor manufacturing process. A silicon substrate cassette is used in such selective etching. In removing the etching residue in non-conductive state occurring in semiconductor manufacturing process, by applying a positive potential to part of conductive silicon substrates in an etching solution, the contact surfaces between the silicon substrates and the portion electrically connected thereto and the chemical etching solution are anodically oxidized to protect with a passive film, while only the etching residue in non-conductive state is selectively removed by isotropic etching, thereby achieving the purpose.

## Claims

### Claim 1

A manufacturing method of semiconductor device, which method comprises:
etching a conductive layer formed on an interlayer insulating film and electrically connected to a surface of an underlying silicon substrate, whereby an etching residue of the conductive layer is formed on the interlayer insulating film; anodically oxidizing the surface of the silicon substrate and a portion of the remaining conductive layer in an alkaline bath to form a passive film thereon; and isotropically etching to remove the residue on the interlayer insulating film in an alkaline bath, wherein anodic oxidation and isotropic etching are conducted at the same time in the same alkaline bath.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the residue on the interlayer insulating film is polycrystalline silicon.

### Claim 3 (depends on 1)

A method according to claim 1, comprising applying a positive potential of several volts to 10 volts to the silicon substrate to effect anodic oxidation.

### Claim 4 (depends on 1)

A method according to claim 1, wherein the chemical etching solution comprises a solution of a member selected from the group consisting of KOH, NaOH, LiOH, CsOH, NH.sub.4 OH, ethylene diamine pyrocatechol, hydrazine, and choline.

### Claim 5 (depends on 1)

A method according to claim 1, wherein the temperature of the chemical etching solution is 60.degree. to 70.degree. C.

### Claim 6 (depends on 1)

A method according to claim 1, wherein the chemical etching solution is 5N KOH solution.

### Claim 7 (depends on 1)

A method according to claim 1, comprising etching two or more silicon substrates at the same time.