# US 2013/0280644 A1 · Mask and method for forming the same

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- Number: US 2013/0280644 A1
- Document ID: US20130280644A1
- Status: Published application
- Kind: A1
- Application number: 13/451,767
- Filed: 2012-04-20
- Published: 2013-10-24
- Earliest claimed: 2012-04-20
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Yun-Yue Lin; Ta-Cheng Lien; Hsin-Chang Lee; Anthony Yen; Chia-Jen Chen
- Web page: https://patentgrep.com/patent/US20130280644A1

## CPC

- G03F 1/48: Protective coatings
- G03F 1/22: Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof
- G03F 1/30: Alternating PSM, e.g. Levenson-Shibuya PSM; Preparation thereof
- G03F 1/32: Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof
- G03F 1/50: Mask blanks not covered by G03F1/20 - G03F1/34; Preparation thereof
- G03F 1/26: Phase shift masks [PSM]; PSM blanks; Preparation thereof
- 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)

## Abstract

A photomask includes a low thermal expansion material (LTEM) substrate, a patterned opaque layer over the LTEM substrate, and a patterned capping layer over the opaque layer. The patterned capping layer includes a transition metal material for suppressing haze growth, such as metal oxide, metal nitride, or metal oxynitride. The material in the capping layer reacts with a hydrogenic compound from a lithography environment to for an atomic level hydrogen passivation layer. The passivation layer has superior ability to suppress photo-induced haze defect growth on the photomask surface, to improve production cycle time and reduce the production cost.

## Claims

### Claim 1

A photomask comprising:
a low thermal expansion material (LTEM) substrate;
a patterned opaque layer over the LTEM substrate; and
a patterned capping layer over the patterned opaque layer, wherein the patterned capping layer includes a transition metal material for suppressing haze growth.

### Claim 2 (depends on 1)

The photomask of claim 1, wherein the LTEM substrate includes one or more from the group consisting of quartz, silicon, silicon carbide, calcium fluoride (CaF2), and silicon oxide-titanium oxide alloy (SiO2—TiO2).

### Claim 3 (depends on 1)

The photomask of claim 1, wherein the patterned opaque layer includes one or more from the group consisting of MoSi, TaON, and TaN.

### Claim 4 (depends on 1)

The photomask of claim 1, wherein the patterned capping layer includes a metal oxide compound (MOx), wherein M is from the group consisting of Si, Ta, Ir, Ru, Hf, and Os.

### Claim 5 (depends on 1)

The photomask of claim 1, wherein the patterned capping layer includes a metal nitride compound (MNx), wherein M is from the group consisting of Si, Ta, Ir, Ru, Hf, and Os.

### Claim 6 (depends on 1)

The photomask of claim 1, wherein the patterned capping layer includes a metal oxynitride compound (MOxNy), wherein M is from the group consisting of Si, Ta, Ir, Ru, Hf, and Os.

### Claim 7 (depends on 1)

The photomask of claim 1, wherein the patterned capping layer includes a crystalline state between amorphous and fine crystal, inclusive.

### Claim 8 (depends on 1)

The photomask of claim 1, wherein the patterned capping layer is configured to react with ionic residue and thereafter produce self-forming efficient surface modified layers to suppress haze or ionic defect growth on a photomask surface during or after a deep ultraviolet (DUV) or extreme ultraviolet (EUV) lithography process.

### Claim 9 (depends on 1)

The photomask of claim 1, wherein the photomask is one of a binary mask and a phase shift mask.

### Claim 10 (depends on 1)

The photomask of claim 1, wherein the photomask includes a binary mask, an alternative phase shift mask (alt. PSM) portion, and an attenuated phase shift mask (att. PSM) portion.

### Claim 11

A method of preparing a photomask, comprising:
depositing an opaque layer on a low thermal expansion material (LTEM) substrate;
depositing a capping layer on the opaque layer, wherein the capping layer includes a material for suppressing haze growth on a surface of the photomask;
depositing a scarified hardmask layer on the capping layer;
patterning the scarified hardmask layer; and
patterning the capping layer and opaque layer using the patterned scarified hardmask layer.

### Claim 12 (depends on 11)

The method according to claim 11, wherein the opaque layer includes MoSi, TaON, TaN, or combinations thereof, and is deposited on the LTEM substrate by one of a sputter deposition, a chemical vapor deposition (CVD), a physical vapor deposition (PVD), a laser deposition, and an atomic layer deposition (ALD) process.

### Claim 13 (depends on 11)

The method according to claim 11, wherein the capping layer includes a metal oxide compound (MOx), wherein M includes Si, Ta, Ir, Ru, Hf, Os, or other transition metal, and is deposited on the opaque layer by one of a sputter deposition, a chemical vapor deposition (CVD), a physical vapor deposition (PVD), a laser deposition, and an atomic layer deposition (ALD) process.

### Claim 14 (depends on 11)

The method according to claim 11, wherein the capping layer includes a metal nitride compound (MNx), wherein M includes Si, Ta, Ir, Ru, Hf, Os, or other transition metal, and is deposited on the opaque layer by one of a sputter deposition, a chemical vapor deposition (CVD), a physical vapor deposition (PVD), a laser deposition, and an atomic layer deposition (ALD) process.

### Claim 15 (depends on 11)

The method according to claim 11, wherein the capping layer includes a metal oxynitride compound (MOxNy), wherein M includes Si, Ta, Ir, Ru, Hf, Os, or other transition metal, and is deposited on the opaque layer by one of a sputter deposition, a chemical vapor deposition (CVD), a physical vapor deposition (PVD), a laser deposition, and an atomic layer deposition (ALD) process.

### Claim 16 (depends on 11)

The method according to claim 11, wherein the scarified hardmask layer includes Cr, CrN, CrO, CrON, or combinations thereof, and is deposited on the opaque layer by one of a sputter deposition, a chemical vapor deposition (CVD), a physical vapor deposition (PVD), a laser deposition, and an atomic layer deposition (ALD) process.

### Claim 17 (depends on 11)

The method according to claim 11, wherein the scarified hardmask layer is patterned using a mask writing technique.

### Claim 18 (depends on 11)

The method according to claim 11, wherein patterning the capping layer and opaque layer includes etching using the patterned scarified hardmask with an etchant that is selective to the capping layer and opaque layer, and thereafter stripping the patterned scarified hardmask with an etchant that is not selective to the capping layer and opaque layer.

### Claim 19

A photomask for suppressing haze growth, the photomask comprising:
a low thermal expansion material (LTEM) substrate;
a patterned opaque layer over the LTEM substrate; and
a patterned capping layer over the patterned opaque layer.

### Claim 20 (depends on 19)

The photomask of claim 19, wherein the patterned capping layer includes a transition metal material for suppressing haze growth.