Photomask and method of forming the same

Patent metadata

Field	Value
Publication number	US-9223199-B2
Application number	US-201314059533-A
Country	US
Kind code	B2
Filing date	Oct 22, 2013
Priority date	Oct 22, 2012
Publication date	Dec 29, 2015
Grant date	Dec 29, 2015

Abstract

A photomask and a method of forming the same, the photomask including a transparent substrate; a light shielding pattern on the transparent substrate, the light shielding pattern including molybdenum and silicon; and an etch stop layer covering at least a sidewall of the light shielding pattern, wherein the etch stop layer has an etch rate lower than an etch rate of the light shielding pattern with respect to an ammonia-based cleaning solution.

First claim

What is claimed is:

1. A photomask, comprising:
a transparent substrate;
a light shielding pattern on the transparent substrate, the light shielding pattern including molybdenum and silicon; and
an etch stop layer covering at least a sidewall of the light shielding pattern,
wherein the etch stop layer has an etch rate lower than an etch rate of the light shielding pattern with respect to an ammonia-based cleaning solution.

2. The photomask as claimed in claim 1 , wherein:
the etch stop layer includes molybdenum, silicon, and nitrogen; and
a nitrogen content of the etch stop layer is higher than a nitrogen content of the light shielding pattern.

3. The photomask as claimed in claim 2 , wherein the nitrogen content of the etch stop layer is about 14 at % to about 28 at % of a molybdenum content of the etch stop layer.

4. The photomask as claimed in claim 1 , wherein:
the light shielding pattern includes a first surface adjacent to the transparent substrate and a second surface spaced apart from the transparent substrate;
the light shielding pattern further includes nitrogen; and
a nitrogen concentration of a portion of the light shielding pattern adjacent to the second surface is higher than a nitrogen concentration of a portion of the light shielding pattern adjacent to the first surface.

5. The photomask as claimed in claim 4 , wherein:
the etch stop layer extends onto the second surface of the light shielding pattern; and
a thickness of the etch stop layer on the second surface is smaller than a thickness of the etch stop layer on a sidewall of the light shielding pattern.

6. The photomask as claimed in claim 4 , wherein:
the light shielding pattern further includes oxygen; and
an oxygen concentration of the portion of the light shielding pattern adjacent to the second surface is lower than an oxygen concentration of the portion of the light shielding pattern adjacent to the first surface.

7. The photomask as claimed in claim 1 , wherein the etch stop layer has a thickness of about 3 nm or less.

8. The photomask as claimed in claim 1 , wherein the etch rate of the etch stop layer is about 10% to about 50% of the etch rate of the light shielding pattern with respect to the ammonia-based cleaning solution.

9. The photomask as claimed in claim 1 , wherein:
the light shielding pattern includes a first surface adjacent to the transparent substrate and a second surface spaced apart from the transparent substrate;
a nitrogen concentration is substantially uniform throughout the light shielding pattern;
the etch stop layer extends onto the second surface; and
the etch stop layer has a substantially uniform thickness regardless of a position of the etch stop layer.

10. The photomask as claimed in claim 1 , wherein the ammonia-based cleaning solution includes at least one of ammonia water (NH 4 OH) and tetramethylammonium hydroxide (TMAH).

11. The photomask as claimed in claim 1 , wherein the light shielding pattern has a light transmittance of substantially 0%.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Oh Jong Keun
• Ko Hyungho
• Shin Inkyun
• Choi Jaehyuck
• Choi Junyoul

Classifications

• G03F1/48 Primary

  Protective coatings · CPC title

• G03F1/80

  Etching · CPC title

• G03F1/54

  Absorbers, e.g. of opaque materials · CPC title

• G03F1/68

  Preparation processes not covered by groups G03F1/20 - G03F1/50 · CPC title

• G03F1/38 Primary

  Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof · CPC title