# US 12,009,224 B2 · Apparatus and method for etching metal nitrides

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- Number: US 12,009,224 B2
- Document ID: US12009224B2
- Status: Granted
- Kind: B2
- Application number: 17/484,144
- Filed: 2021-09-24
- Published: 2022-03-31
- Granted: 2024-06-11
- Earliest claimed: 2020-09-29
- Assignees: ASM IP Holding B.V.
- Applicants: ASM IP Holding B.V.
- Inventors: Ren-Jie Chang; Giuseppe Alessio Verni; Qi Xie
- Web page: https://patentgrep.com/patent/US12009224B2

## CPC

- H10P 50/267: {using plasmas}
- C23C 16/34: Nitrides {(C23C16/303 takes precedence)}
- C23C 16/56: After-treatment
- H01J 37/32357: {Generation remote from the workpiece, e.g. down-stream}
- H01J 37/3244: {Gas supply means}
- H01J 37/32834: {Exhausting}
- H10P 14/6314: {of a metallic layer}
- H10P 50/285: {of materials not containing Si, e.g. PZT or Al2O3}
- H01J 2237/334: Etching
- H01J 2237/338: Changing chemical properties of treated surfaces
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

Devices and methods for selectively etching a metal nitride layer are disclosed. The methods comprise an oxidation step and an etching step which are optionally separated by a purge, and which can be repeated in a cyclical etching process.

## Claims

### Claim 1

A method for etching a metal nitride layer disposed on a substrate, the method comprising:
providing a substrate in a reaction chamber of a semiconductor processing device, the substrate comprising a metal nitride layer, wherein the metal nitride layer comprises at least one of vanadium nitride and molybdenum nitride;
the method further comprising executing one or more etching cycles, an etching cycle comprising the following steps, in the following order:
an oxidation step that comprises providing a gaseous oxidizing agent as a gaseous oxidizing agent pulse to the reaction chamber, thereby oxidizing a surface layer of the metal nitride layer, thus forming a metal oxide surface layer overlying an unaffected metal nitride layer; and
an etching step that comprises providing only a gaseous etchant as a gaseous etchant pulse to the reaction chamber and exciting the gaseous etchant with plasma, thereby forming an excited gaseous etchant and selectively etching the metal oxide surface layer with respect to the unaffected metal nitride layer, wherein the gaseous etchant consists of one of HCl, CCl4, BCl4, and Cl2 and optionally a noble gas.

### Claim 2 (depends on 1)

The method according to claim 1 wherein the gaseous oxidizing agent is selected from the list consisting of O2, O3, H2O, and H2O2.

### Claim 3 (depends on 1)

The method according to claim 1 wherein the oxidation step comprises generating an O2 plasma in the reaction chamber.

### Claim 4 (depends on 1)

The method according to claim 1 wherein the oxidation step and the etching step are separated by a post-oxidation purge step.

### Claim 5 (depends on 4)

The method according to claim 4 wherein at least one of the post-oxidation purge step and a post-etch purge step comprise providing a purge gas to the reaction chamber.

### Claim 6 (depends on 5)

The method according to claim 5 wherein the purge gas comprises N2 or a noble gas.

### Claim 7 (depends on 4)

The method according to claim 4 wherein at least one of the post-oxidation purge step and a post-etch purge step comprise evacuating the reaction chamber.

### Claim 8 (depends on 1)

The method according to claim 1 comprising two or more etching cycles, wherein subsequent etching cycles are separated by a post-etch purge step.

### Claim 9 (depends on 1)

The method of claim 1, wherein the providing the substrate in the reaction chamber further comprises moving the substrate from a metal nitride deposition system to a metal nitride etching system, the metal nitride etching system comprising the reaction chamber of the semiconductor processing device.

### Claim 10 (depends on 1)

The method of claim 1, wherein the plasma is provided by a direct plasma unit positioned in the reaction chamber.