# US 11,028,479 B2 · Method of forming film

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- Number: US 11,028,479 B2
- Document ID: US11028479B2
- Status: Granted
- Kind: B2
- Application number: 16/199,789
- Filed: 2018-11-26
- Published: 2019-05-30
- Granted: 2021-06-08
- Earliest claimed: 2017-11-28
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Katsumasa Yamaguchi; Takashi Sameshima
- Web page: https://patentgrep.com/patent/US11028479B2

## CPC

- C23C 16/45553: {characterized by the use of precursors specially adapted for ALD}
- C23C 16/0272: {Deposition of sub-layers, e.g. to promote the adhesion of the main coating}
- C23C 16/045: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates}
- C23C 16/08: from metal halides
- C23C 16/14: Deposition of only one other metal element
- C23C 16/45527: {characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations}
- 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)

## Abstract

A method of forming a tungsten film on a surface of a target substrate having a base film is performed by repeating a cycle plural times. The cycle includes alternately supplying a tungsten chloride gas and a reducing gas for reducing the tungsten chloride gas, with a purge interposed therebetween, into a process container in which the target substrate is accommodated and that is maintained under a depressurized atmosphere. The method includes setting a supply flow rate of the tungsten chloride gas and a time of the cycle such that a ratio of a thickness of the base film etched by repeating the cycle the plural times to a thickness of the base film before repeating the cycle the plural times becomes smaller than a predetermined ratio in a state where an integrated flow rate of the tungsten chloride gas per one cycle is kept substantially constant.

## Claims

### Claim 1

A method of forming a tungsten film on a surface of a target substrate having a base film by repeating a cycle plural times, the cycle including alternately supplying a tungsten chloride gas and a reducing gas for reducing the tungsten chloride gas, with a purge interposed therebetween, into a process container in which the target substrate is accommodated and that is maintained under a depressurized atmosphere, the method comprising:
setting an integrated flow rate of the tungsten chloride gas per one cycle to be substantially constant while the tungsten film is formed on the target substrate; and
shortening a time of the cycle while increasing a supply flow rate of the tungsten chloride gas within a range where a ratio of a thickness of the base film etched by repeating the cycle the plural times to a thickness of the base film before repeating the cycle the plural times becomes smaller than a predetermined ratio, in a state where the integrated flow rate of the tungsten chloride gas per one cycle is kept substantially constant.

### Claim 2 (depends on 1)

The method of claim 1, wherein the predetermined ratio is 50%.

### Claim 3 (depends on 1)

The method of claim 1, wherein the tungsten chloride gas is one selected from the group consisting of a WCl6 gas, a WCl5 gas and a WCl4 gas.

### Claim 4 (depends on 1)

The method of claim 1, wherein the reducing gas is at least one selected from the group consisting of a H2 gas, a SiH4 gas, a B2H6 gas and an NH3 gas.

### Claim 5 (depends on 1)

The method of claim 1, wherein the base film is one selected from the group consisting of a TiN film and a TiSiN film.