# US 8,785,083 B2 · Systems and methods for lithography masks

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- Number: US 8,785,083 B2
- Document ID: US8785083B2
- Status: Granted
- Kind: B2
- Application number: 13/486,015
- Filed: 2012-06-01
- Published: 2013-12-05
- Granted: 2014-07-22
- Earliest claimed: 2012-06-01
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Chih-Chiang Tu; Hsin-Chang Lee; Jong-Yuh Chang; Chia-Jen Chen; Chun-Lang Chen
- Inventors: Chih-Chiang Tu; Hsin-Chang Lee; Jong-Yuh Chang; Chia-Jen Chen; Chun-Lang Chen
- Web page: https://patentgrep.com/patent/US8785083B2

## CPC

- G03F 1/36: Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
- G03F 1/50: Mask blanks not covered by G03F1/20 - G03F1/34; Preparation thereof
- G03F 1/58: having two or more different absorber layers, e.g. stacked multilayer absorbers
- G03F 1/80: Etching
- 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

Structure of mask blanks and masks, and methods of making masks are disclosed. The new mask blank and mask comprise a tripe etching stop layer to prevent damages to the quartz substrate when the process goes through etching steps three times. The triple etching stop layer may comprise a first sub-layer of tantalum containing nitrogen (TaN), a second sub-layer of tantalum containing oxygen (TaO), and a third sub-layer of TaN. Alternatively, the triple etching stop layer may comprise a first sub-layer of SiON material, a second sub-layer of TaO material, and a third sub-layer of SiON material. Another alternative may be one layer of low etching rate MoxSiyONz material which can prevent damages to the quartz substrate when the process goes through etching steps three times. The island mask is defined on the mask blank by using various optical proximity correction rules.

## Claims

### Claim 1

A mask blank, comprising:
a substrate;
a triple etching stop layer on the substrate, wherein the triple etching stop layer comprises a first sub-layer of SiON material, a second sub-layer of TaO material on the first sub-layer, and a third sub-layer of SiON material on the second sub-layer;
a shielding layer on the triple etching stop layer; and
a hard mask layer on the shielding layer.

### Claim 2 (depends on 1)

The mask blank of claim 1, further comprising a positive chemical amplified resist layer on the hard mask layer.

### Claim 3 (depends on 1)

The mask blank of claim 1, wherein the first sub-layer, the sub-layer, and the third sub-layer of the triple etching stop layer are with a reflectivity less than about 15%, an extinction coefficient k ranged about 0.55˜0.65, and a refractive index n ranged about 2.4˜2.6.

### Claim 4 (depends on 1)

The mask blank of claim 1, wherein the shielding layer comprises a molybdenum silicide oxynitride (MoxSiyONz) material or a molybdenum silicon material.

### Claim 5 (depends on 1)

The mask blank of claim 1, wherein the shielding layer is replaced by a half-tone layer.

### Claim 6 (depends on 5)

The mask blank of claim 5, wherein the half-tone layer comprises a material selected from a group consisting essentially of chromium oxy-nitride (CrON), chromium oxide (CrO), molybdenum silicon oxy-nitride (MoxSiyONz), amorphous carbon, or silicon nitride (SiN).

### Claim 7 (depends on 1)

The mask blank of claim 1, wherein the substrate is a quartz substrate.

### Claim 8 (depends on 1)

The mask blank of claim 1, wherein the hard mask layer comprises chrome.

### Claim 9

A mask comprising:
a substrate;
an island on the substrate, having a triple etching stop layer on the substrate, and a shielding layer on the triple etching stop layer, wherein the triple etching stop layer of the island comprises a first sub-layer of SiON material, a second sub-layer of TaO material on the first sub-layer, and a third sub-layer of SiON material on the second sub-layer.