# US 2021/0242030 A1 · Plasma processing method and etching apparatus

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- Number: US 2021/0242030 A1
- Document ID: US20210242030A1
- Status: Published application
- Kind: A1
- Application number: 16/646,057
- Filed: 2019-04-22
- Published: 2021-08-05
- Earliest claimed: 2019-04-22
- Assignees: Hitachi High-Technologies Corporation
- Applicants: Hitachi High-Technologies Corporation
- Inventors: Kazunori SHINODA; Hiroto OTAKE; Hiroyuki KOBAYASHI; Kohei KAWAMURA; Masaru IZAWA
- Web page: https://patentgrep.com/patent/US20210242030A1

## CPC

- H10P 50/283: {by chemical means}
- H01J 37/18: Vacuum locks {; Means for obtaining or maintaining the desired pressure within the vessel}
- H01J 37/32449: {Gas control, e.g. control of the gas flow}
- H10P 14/687: {the materials being fluorocarbon compounds, e.g. (CHxFy) n or polytetrafluoroethylene}
- H10P 50/242: {of Group IV materials}
- H10P 50/267: {using plasmas}
- H01J 2237/3344: isotropy
- H10B 41/27: the channels comprising vertical portions, e.g. U-shaped channels
- H10B 43/27: the channels comprising vertical portions, e.g. U-shaped channels
- 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)
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

The present invention provides a plasma processing method or a plasma processing method, which allows the evenness of etching amounts to increase and the yield of processing to improve. A method for etching a tungsten film includes: a first step of depositing a fluorocarbon layer and forming an intermediate layer that contains tungsten and fluorine and is self-limiting between the fluorocarbon layer and the tungsten film by supplying plasma of an organic gas containing fluorine to a base material having the tungsten film over at least a part of the surface; and a second step of removing the fluorocarbon layer and the intermediate layer by using plasma of an oxygen gas.

## Claims

### Claim 1

A plasma processing method comprising:
a first processing step of arranging a wafer to be processed in a processing chamber, supplying plasma of an organic gas containing fluorine into the processing chamber, depositing a fluorocarbon layer over the upper surface of a film layer to be processed that is formed over the upper surface of the wafer beforehand and contains tungsten, and forming an intermediate layer that contains tungsten and fluorine in the film layer to be processed and is self-limiting between the fluorocarbon layer and the film layer to be processed; and
a second processing step of supplying particles in plasma formed in the processing chamber by using a gas containing oxygen to the upper surface of the film layer to be processed and removing the fluorocarbon layer and the intermediate layer.

### Claim 2 (depends on 1)

The plasma processing method according to claim 1, wherein:
the first step includes, after depositing the fluorocarbon layer, a step of heating the upper surface of the wafer and forming the intermediate layer having the self-limiting nature; and
the second step includes, after supplying the particles in the plasma using the gas containing oxygen and removing the fluorocarbon layer, a step of heating the wafer and removing the intermediate layer.

### Claim 3 (depends on 2)

The plasma processing method according to claim 2, wherein the wafer is heated by irradiating the upper surface of the wafer with infrared at the first or second step.

### Claim 4 (depends on 2)

The plasma processing method according to claim 2, wherein multiple steps including the step of removing the fluorocarbon layer and the step of removing the intermediate layer by heating the wafer in the second step are regarded as one cycle and the cycle is repeated multiple times.

### Claim 5

An etching apparatus of etching a tungsten film, comprising:
a processing chamber;
an object to be processed that is placed in the processing chamber and has a tungsten film over at least a part of the surface;
a stage for placing the object to be processed;
a cooling means for cooling the object to be processed;
a plasma source for supplying plasma of an organic gas containing fluorine and plasma of an oxygen gas to the processing chamber;
a vacuum pump for depressurizing the processing chamber; and
a heating means for heating the object to be processed.