# US 5,705,433 A · Etching silicon-containing materials by use of silicon-containing compounds

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- Number: US 5,705,433 A
- Document ID: US5705433A
- Status: Granted
- Kind: A
- Application number: 08/518,937
- Filed: 1995-08-24
- Granted: 1998-01-06
- Earliest claimed: 1995-08-24
- Assignees: Applied Materials, Inc.
- Inventors: Dale A. Olson; Xue-Yu Qian; Patty Hui-ing Tsai
- Web page: https://patentgrep.com/patent/US5705433A

## CPC

- H10P 50/268: {of silicon-containing layers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

During the etching of a silicon-containing material using a halogen-containing etch gas, a silicon-hydride gas is added to the etch gas to provide increased sidewall protection during the etch. Suitably up to about 50 percent by volume of a silicon-containing gas such as silane is added to improve anisotropy of the etch and to prevent notching at the silicon-substrate interface.

## Claims

### Claim 1

In a process for anisotropically etching openings in silicon-containing materials with a halogen etch gas selected from the group consisting of a halogen and a hydrogen halide, the improvement comprising adding a silicon-hydride gas to the etch gas, thereby depositing a protective silicon-containing layer on etched sidewalls of said openings.

### Claim 2 (depends on 1)

A process according to claim 1 wherein the silicon-containing material is polysilicon.

### Claim 3 (depends on 1)

A process according to claim 1 wherein the silicon-containing material is a refractory metal silicide.

### Claim 4 (depends on 1)

A process according to claim 1 wherein the silicon-containing material is a refractory metal silicide-polysilicon stack.

### Claim 5 (depends on 1)

A process according to claim 1 wherein the silicon-hydride gas is silane (SiH.sub.4).

### Claim 6 (depends on 1)

A process according to claim 1 wherein the silicon-hydride gas is added during a main etch step.

### Claim 7 (depends on 1)

A process according to claim 1 wherein the silicon-hydride gas is added during an overetch step.

### Claim 8 (depends on 1)

A process according to claim 1 wherein the etch gas includes chlorine.

### Claim 9 (depends on 1)

A process according to claim 1 wherein the etch gas is a mixture including chlorine and hydrogen bromide.

### Claim 10 (depends on 1)

A process according to claim 1 wherein the silicon-hydride gas is added to the etch gas in amounts up to 50 percent by volume.