# US 10,121,674 B2 · Method for etching silicon layer and plasma processing apparatus

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- Number: US 10,121,674 B2
- Document ID: US10121674B2
- Status: Granted
- Kind: B2
- Application number: 15/654,947
- Filed: 2017-07-20
- Published: 2017-11-09
- Granted: 2018-11-06
- Earliest claimed: 2013-12-11
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Akinori Kitamura; Eiji Suzuki
- Web page: https://patentgrep.com/patent/US10121674B2

## CPC

- H10P 50/242: {of Group IV materials}
- H01J 37/32192: {Microwave generated discharge (H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence)}
- H01J 37/32449: {Gas control, e.g. control of the gas flow}
- H10P 50/283: {by chemical means}
- H10P 70/20: {Cleaning during device manufacture}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

Disclosed is a method of etching a silicon layer by removing an oxide film formed on a workpiece which includes the silicon layer and a mask provided on the silicon layer. The method includes: (a) forming a denatured region by generating plasma of a first processing gas containing hydrogen, nitrogen, and fluorine within a processing container accommodating the workpiece therein to denature an oxide film formed on a surface of the workpiece; (b1) removing the denatured region by generating plasma of a rare gas within the processing container; and (c) etching the silicon layer by generating plasma of a second processing gas within the processing container.

## Claims

### Claim 1

A method of etching a silicon layer of an object to be processed (“workpiece”), the method comprising:
forming a denatured region by generating plasma of a first processing gas containing hydrogen, nitrogen, and fluorine within a processing container accommodating the workpiece therein to denature an oxide film formed on a surface of the workpiece including a mask provided on the silicon layer;
removing the denatured region by generating plasma of a rare gas within the processing container; and
etching the silicon layer by generating plasma of a second processing gas within the processing container.

### Claim 2

A method of etching a silicon layer of an object to be processed (“workpiece”), the method comprising:
forming a denatured region by generating plasma of a first processing gas containing hydrogen, nitrogen, and fluorine within a processing container accommodating the workpiece therein to denature an oxide film formed on a surface of the workpiece including a mask provided on the silicon layer;
removing the denatured region by generating plasma of a second processing gas within the processing container following to forming the denatured region without taking out the workpiece from the processing container; and
etching the silicon layer by generating plasma of the second processing gas within the processing container.

### Claim 3 (depends on 1)

The method of claim 1, wherein the forming of the denatured region and the removing of the denatured region are performed in a biasless manner.

### Claim 4 (depends on 1)

The method of claim 1, wherein the first processing gas includes SF6 gas.

### Claim 5 (depends on 2)

The method of claim 2, wherein the forming of the denatured region and the removing of the denatured region are performed in a biasless manner.

### Claim 6 (depends on 2)

The method of claim 2, wherein the first processing gas includes SF6 gas.