# US 11,442,357 B2 · Mask blank, phase-shift mask, and method of manufacturing semiconductor device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,442,357 B2
- Document ID: US11442357B2
- Status: Granted
- Kind: B2
- Application number: 17/058,631
- Filed: 2019-05-08
- Published: 2021-07-08
- Granted: 2022-09-13
- Earliest claimed: 2018-05-30
- Assignees: Hoya Corporation
- Applicants: Hoya Corporation
- Inventors: Hitoshi Maeda; Hiroaki Shishido; Masahiro Hashimoto
- Web page: https://patentgrep.com/patent/US11442357B2

## CPC

- G03F 1/26: Phase shift masks [PSM]; PSM blanks; Preparation thereof
- G03F 1/32: Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof
- G03F 7/20: Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00)
- H10P 76/405: {characterised by their composition, e.g. multilayer masks}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Provided is a mask blank, including a phase shift film. The phase shift film has a structure where a first layer and a second layer are stacked in this order from a side of the transparent substrate. The first layer is provided in contact with a surface of the transparent substrate. Refractive indexes n1 and n2 of the first layer and the second layer, respectively, at a wavelength of an exposure light of an ArF excimer laser satisfy the relation n1<n2. Extinction coefficients k1 and k2 of the first layer and the second layer, respectively, at a wavelength of the exposure light satisfy the relation k1<k2. Film thicknesses d1 and d2 of the first layer and the second layer, respectively, satisfy the relation d1<d2.

## Claims

### Claim 1

A mask blank comprising a phase shift film on a transparent substrate,
wherein the phase shift film comprises:
a first layer that is provided in contact with a surface of the transparent substrate and has a film thickness d1, the first layer contains silicon, nitrogen, and oxygen, and
a second layer that is provided on the first layer and has a film thickness d2 which is greater than d1, and
wherein, at a wavelength of 193 nm:
the first layer has a refractive index n1 and an extinction coefficient k1, and
the second layer has a refractive index n2 that is greater than n1 and an extinction coefficient k2 that is greater than k1.

### Claim 2 (depends on 1)

The mask blank according to claim 1, wherein the refractive index n1 of the first layer is 1.8 or more and the extinction coefficient k1 of the first layer is 0.15 or less.

### Claim 3 (depends on 1)

The mask blank according to claim 1, wherein the refractive index n2 of the second layer is 2.2 or more and the extinction coefficient k2 of the second layer is 0.2 or more.

### Claim 4 (depends on 1)

The mask blank according to claim 1,
wherein, at the wavelength of 193 nm, the transparent substrate has a refractive index ns that is less than n1 and an extinction coefficient ks that is less than k1.

### Claim 5 (depends on 4)

The mask blank according to claim 4, wherein the refractive index ns of the transparent substrate is 1.6 or less and the extinction coefficient ks of the transparent substrate is 0.01 or less.

### Claim 6 (depends on 1)

The mask blank according to claim 1, wherein a transmittance of the phase shift film with respect to a light having a wavelength of 193 nm is 15% or more, and
wherein the phase shift film is configured to transmit the light so that transmitted light has a phase difference of 150 degrees or more and 200 degrees or less with respect to the light transmitted through air for a same distance as a thickness of the phase shift film.

### Claim 7 (depends on 1)

The mask blank according to claim 1,
wherein the second layer contains silicon and nitrogen.

### Claim 8 (depends on 7)

The mask blank according to claim 7, wherein a nitrogen content of the second layer is more than a nitrogen content of the first layer.

### Claim 9 (depends on 1)

The mask blank according to claim 1, wherein the phase shift film comprises a third layer on the second layer, and
wherein, at the wavelength of 193 nm, the third layer has a refractive index n3 that is less than n1 and an extinction coefficient ks that is greater than k2.

### Claim 10 (depends on 9)

The mask blank according to claim 9, wherein a film thickness d3 of the third layer is less than d1.

### Claim 11 (depends on 9)

The mask blank according to claim 9, wherein the refractive index n3 of the third layer is less than 1.8, and the extinction coefficient k3 of the third layer is 1.0 or more.

### Claim 12 (depends on 9)

The mask blank according to claim 9, wherein the third layer contains silicon and nitrogen.

### Claim 13 (depends on 9)

The mask blank according to claim 9, wherein the phase shift film comprises a fourth layer on the third layer, and
wherein, at the wavelength of 193 nm, the fourth layer has a refractive index n4 that is less than n1 and an extinction coefficient k4 that is less than k1.

### Claim 14 (depends on 13)

The mask blank according to claim 13, wherein the refractive index n4 of the fourth layer is 1.7 or less and the extinction coefficient k4 of the fourth layer is 0.02 or less.

### Claim 15 (depends on 13)

The mask blank according to claim 13, wherein the fourth layer contains silicon and oxygen.

### Claim 16 (depends on 1)

The mask blank according to claim 1, wherein the phase shift film comprises a third A layer on the second layer,
wherein, at the wavelength of 193 nm, the third A layer has a refractive index n3A that is less than n1 and an extinction coefficient k3A that is less than k1.

### Claim 17 (depends on 16)

The mask blank according to claim 16, wherein the refractive index n3A of the third A layer is 1.7 or less, and the extinction coefficient k3A of the third A layer is 0.02 or less.

### Claim 18 (depends on 16)

The mask blank according to claim 16, wherein the third A layer contains silicon and oxygen.

### Claim 19 (depends on 1)

A phase shift mask provided with a transfer pattern on the phase shift film of the mask blank according to claim 1.

### Claim 20 (depends on 19)

A method of manufacturing a semiconductor device comprising using the phase shift mask according to claim 19 and subjecting a resist film on a semiconductor substrate to exposure-transfer of a transfer pattern.