# US 10,480,078 B2 · Plasma atomic layer deposition

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- Number: US 10,480,078 B2
- Document ID: US10480078B2
- Status: Granted
- Kind: B2
- Application number: 16/116,321
- Filed: 2018-08-29
- Published: 2018-12-20
- Granted: 2019-11-19
- Earliest claimed: 2014-03-31
- Assignees: ASM IP Holdings B.V.
- Applicants: Asm IP Holding B.V.
- Inventors: Harm C. M. Knoops; Koen de Peuter; Wilhelmus M. M. Kessels
- Web page: https://patentgrep.com/patent/US10480078B2

## CPC

- C23C 16/52: Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)}
- C23C 16/345: {Silicon nitride}
- C23C 16/45542: {Plasma being used non-continuously during the ALD reactions}
- H10P 14/6336: {in the presence of a plasma [PECVD]}
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/6687: {the compound comprising silicon and nitrogen}
- H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz}
- 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)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Plasma atomic layer deposition (ALD) is optimized through modulation of the gas residence time during an excited species phase, wherein activated reactant is supplied such as from a plasma. Reduced residence time increases the quality of the deposited layer, such as reducing wet etch rates, increasing index of refraction and/or reducing impurities in the layer. For example, dielectric layers, particularly silicon nitride films, formed from such optimized plasma ALD processes have low levels of impurities remaining from the silicon precursor.

## Claims

### Claim 1

A method of depositing a layer of dielectric silicon nitride by plasma atomic layer deposition, the method comprising:
providing a substrate in a reaction space;
in a first phase, contacting the substrate with a silicon precursor to adsorb an adsorbed species of the silicon precursor on the substrate; and
in a second phase, contacting the substrate with excited nitrogen species to react with the adsorbed species, wherein the residence time of the excited species in the reaction space during the second phase is less than about 1.0 s, and
cyclically repeating the first phase and second phase to form a dielectric SiN layer of a desired thickness.

### Claim 2 (depends on 1)

The method of claim 1, wherein the excited nitrogen species is supplied to or formed in the reaction space for greater than about 0.1 s.

### Claim 3 (depends on 1)

The method of claim 1, further comprising purging the reaction space between the first phase and the second phase.

### Claim 4 (depends on 1)

The method of claim 1, wherein in the second phase the excited nitrogen species replace the ligands with nitrogen to leave a layer of dielectric SiN.

### Claim 5 (depends on 1)

The method of claim 1, wherein the silicon precursor is organic, and the layer of dielectric SiN contains less than 2 atomic % carbon.

### Claim 6 (depends on 1)

The method of claim 1, wherein the silicon precursor is a halide and the layer of dielectric SiN contains less than about 2 atomic % of a halogen from the silicon precursor.

### Claim 7 (depends on 1)

The method of claim 1, wherein the silicon precursor comprises a silicon amine.

### Claim 8 (depends on 7)

The method of claim 7, wherein the silicon precursor comprises BTBAS.

### Claim 9 (depends on 1)

The method of claim 1, wherein in the second phase the excited nitrogen species are supplied from a remote plasma unit.

### Claim 10 (depends on 1)

The method of claim 1, wherein the second phase comprises generating a plasma from nitrogen gas alone, and supplying the excited nitrogen species from the plasma.

### Claim 11 (depends on 1)

The method of claim 1, wherein the second phase comprises generating a plasma from nitrogen gas and hydrogen gas, and supplying the excited nitrogen species from the plasma.

### Claim 12 (depends on 1)

The method of claim 1, wherein the layer of dielectric silicon nitride has an index of refraction greater than about 1.9.

### Claim 13 (depends on 1)

The method of claim 1, wherein the layer of dielectric silicon nitride has an etch rate of less than about 1.5 nm/min in a buffered, 7:1 dilute HF solution.

### Claim 14

A method of depositing a SiN film on a substrate in a reaction space, the method comprising:
contacting the substrate with a silicon precursor; and
subsequently contacting the substrate with excited nitrogen species, wherein the residence time of the excited nitrogen species in the reaction space is less than about 1.0 s, and
repeating contacting the substrate with the silicon precursor and the excited nitrogen species to form a film consisting essentially of dielectric SiN.

### Claim 15 (depends on 14)

The method of claim 14, further comprising purging the reaction space between contacting the substrate with the silicon precursor and contacting the substrate with the excited nitrogen species.

### Claim 16 (depends on 14)

The method of claim 14, wherein the excited nitrogen species is supplied to or formed in the reaction space for greater than about 0.1 s.

### Claim 17 (depends on 14)

The method of claim 14, wherein the excited nitrogen species are supplied from a remote plasma unit.

### Claim 18 (depends on 14)

The method of claim 14, wherein the silicon precursor comprises a silicon amine.

### Claim 19 (depends on 14)

The method of claim 14, wherein the deposited SiN film has an index of refraction greater than about 1.9.

### Claim 20 (depends on 14)

The method of claim 14, wherein the deposited SiN film has an etch rate of less than about 1.5 nm/min in a buffered, 7:1 dilute HF solution.