# US 6,720,118 B2 · Enhanced inspection of extreme ultraviolet mask

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- Number: US 6,720,118 B2
- Document ID: US6720118B2
- Status: Granted
- Kind: B2
- Application number: 10/423,733
- Filed: 2003-04-25
- Published: 2003-10-30
- Granted: 2004-04-13
- Earliest claimed: 2001-03-30
- Assignees: Intel Corporation
- Inventors: Pei-Yang Yan; Ted Liang; Guojing Zhang
- Web page: https://patentgrep.com/patent/US6720118B2

## CPC

- G03F 1/84: Inspecting
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- B82Y 40/00: Manufacture or treatment of nanostructures
- G03F 1/24: Reflection masks; 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)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

The present invention discloses a method of increasing the contrast of an EUV mask at inspection by forming a multilayer mirror over a substrate; forming an absorber layer over the multilayer mirror; forming a top layer over the absorber layer; patterning the mask into a first region and a second region; and removing the top layer and the absorber layer in the first region.

## Claims

### Claim 1

A mask comprising:
a substrate;
a multilayer mirror disposed over said substrate, said multilayer mirror having a first region and a second region;
an absorber layer disposed over said second region of said multilayer mirror, said absorber layer being absorbent at a first wavelength; and
a top layer disposed over said absorber layer, said top layer being absorbent at a second wavelength.

### Claim 2 (depends on 1)

The mask of claim 1 wherein said substrate has a low coefficient of thermal expansion.

### Claim 3 (depends on 1)

The mask of claim 1 wherein said first wavelength comprises Extreme Ultraviolet (EUV) wavelength.

### Claim 4 (depends on 1)

The mask of claim 1 wherein said second wavelength comprises Ultraviolet (UV) or Deep Ultraviolet (DUV) wavelength.

### Claim 5 (depends on 1)

The mask of claim 1 wherein said multilayer mirror comprises alternating layers of a high index of refraction material and a low index of refraction material.

### Claim 6 (depends on 1)

The mask of claim 1 wherein said multilayer mirror comprises Molybdenum and Silicon.

### Claim 7 (depends on 1)

The mask of claim 1 wherein a buffer layer is further disposed over said multilayer mirror and below said absorber layer in said second region.

### Claim 8 (depends on 1)

The mask of claim 1 wherein said absorber layer comprises a metal.

### Claim 9 (depends on 1)

The mask of claim 1 wherein said absorber layer comprises an alloy.

### Claim 10 (depends on 1)

The mask of claim 1 wherein said absorber layer comprises a ceramic.

### Claim 11 (depends on 1)

The mask of claim 1 wherein said top layer comprises a metal.

### Claim 12 (depends on 1)

The mask of claim 1 wherein said top layer comprises an alloy.

### Claim 13 (depends on 1)

The mask of claim 1 wherein said top layer comprises a ceramic.

### Claim 14 (depends on 1)

The mask of claim 1 wherein said top layer comprises Fluorine.

### Claim 15 (depends on 1)

The mask of claim 1 wherein said top layer comprises Oxygen.

### Claim 16 (depends on 1)

The mask of claim 1 wherein said top layer comprises Argon.

### Claim 17 (depends on 1)

The mask of claim 1 wherein said top layer comprises Carbon.

### Claim 18 (depends on 1)

The mask of claim 1 wherein said top layer comprises Hydrogen.