Methods and chemical solutions for cleaning photomasks using quaternary ammonium hydroxides

Patent metadata

Field	Value
Publication number	US-2016304815-A1
Application number	US-201615132480-A
Country	US
Kind code	A1
Filing date	Apr 19, 2016
Priority date	Apr 20, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

Embodiments provided herein describe methods and chemical solutions for cleaning photomasks. A photomask is provided. The photomask is exposed to a chemical solution. The chemical solution includes a quaternary ammonium hydroxide.
The quaternary ammonium hydroxide may include at least one of tetraethyl ammonium hydroxide (TEAH), tetrapropyl ammonium hydroxide (TPAH), or a combination thereof. The photomask may be an extreme ultraviolet (EUV) lithography photomask.

First claim

What is claimed:

1 . A method comprising:
providing a photomask; and exposing the photomask to a chemical solution, wherein the chemical solution comprises a quaternary ammonium hydroxide.

2 . The method of claim 1 , wherein the photomask is an extreme ultraviolet (EUV) lithography photomask.

3 . The method of claim 2 , wherein the quaternary ammonium hydroxide comprises at least one of tetraethyl ammonium hydroxide (TEAH), tetrapropyl ammonium hydroxide (TPAH), or a combination thereof.

4 . The method of claim 3 , wherein the photomask comprises ruthenium.

5 . The method of claim 4 , wherein the photomask further comprises tantalum, molybdenum, and silicon.

6 . The method of claim 5 , wherein the chemical solution further comprises a surfactant, wherein the surfactant comprises at least one of t-octylphenoxypolyethoxyethanol, trimethylnonylpolyethylene glycol, or a combination thereof.

7 . The method of claim 6 , wherein the chemical solution further comprises at least one of diethylenetriamine (DETA), n-methyl-2-pyrrolidone (NMP), or a combination thereof.

8 . The method of claim 7 , wherein the chemical solution comprises about 15 mass % TEAH, about 1 mass % t-octylphenoxypolyethoxyethanol, and about 0.1 mass % DETA.

9 . The method of claim 8 , wherein the chemical solution is heated to about 80° C. when the photomask is exposed to the chemical solution.

10 . The method of claim 7 , wherein the chemical solution comprises about 10 mass % TPAH, about 1 mass % t-octylphenoxypolyethoxyethanol, and about 0.1 mass % DETA.

11 . A method for cleaning a photomask, the method comprising:
providing a photomask, wherein the photomask comprises ruthenium, tantalum, molybdenum, and silicon; and exposing the photomask to a cleaning solution, wherein the cleaning solution comprises a quaternary ammonium hydroxide and a surfactant.

12 . The method of claim 11 , wherein the quaternary ammonium hydroxide comprises at least one of tetraethyl ammonium hydroxide (TEAH), tetrapropyl ammonium hydroxide (TPAH), or a combination thereof.

13 . The method of claim 12 , wherein the surfactant comprises at least one of t-octylphenoxypolyethoxyethanol, trimethylnonylpolyethylene glycol, or a combination thereof.

14 . The method of claim 13 , wherein the cleaning solution further comprises at least one of diethylenetriamine (DETA), n-methyl-2-pyrrolidone (NMP), or a combination thereof.

15 . The method of claim 13 , wherein the photomask comprises:
a substrate; a multi-layer stack formed above the substrate, wherein the multi-layer stack comprises a plurality of alternating first and second layers, the first layers comprising molybdenum and the second layers comprising silicon; a capping layer formed above the multi-layer stack, wherein the capping layer comprises ruthenium; and an absorber layer formed above the capping layer, wherein the absorber layer comprises tantalum.

16 . A chemical solution for cleaning an extreme ultraviolet (EUV) lithography photomask comprising ruthenium, wherein the solution comprises:
a quaternary ammonium hydroxide; a surfactant; at least one of diethylenetriamine (DETA), n-methyl-2-pyrrolidone (NMP), or a combination thereof; and water.

17 . The chemical solution of claim 16 , wherein the chemical solutions comprises not more than about 20 mass % of the quaternary ammonium hydroxide, not more than about 5 mass % of the surfactant, and not more than about 20 mass % of the at least one of DETA, NMP, or a combination thereof.

18 . The chemical solution of claim 17 , wherein the quaternary ammonium hydroxide comprises at least one of tetraethyl ammonium hydroxide (TEAH), tetrapropyl ammonium hydroxide (TPAH), or a combination thereof, and the surfactant consists of at least one of t-octylphenoxypolyethoxyethanol, trimethylnonylpolyethylene glycol, or a combination thereof.

19 . The chemical solution of claim 18 , wherein the chemical solution comprises about 15 mass % TEAH, about 0.1 mass % t-octylphenoxypolyethoxyethanol, about 0.1 mass % DETA, and water.

20 . The chemical solution of claim 18 , wherein the chemical solution comprises about 7 mass % TPAH, about 0.1 mass % t-octylphenoxypolyethoxyethanol, about 0.1 mass % by DETA, and water.

Assignees

• Intermolecular Inc
• Samsung Electronics Co Ltd

Inventors

• Lowe Jeffrey
• Van Berkel Kim
• Choi Jae-Hyuck

Classifications

• C11D3/30 Primary

  Amines; Substituted amines {; Quaternized amines} · CPC title

• B08B3/08

  the liquid having chemical or dissolving effect · CPC title

• G03F1/82

  Auxiliary processes, e.g. cleaning or inspecting · CPC title

• B08B3/10

  with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration · CPC title

• C11D3/28

  Heterocyclic compounds containing nitrogen in the ring · CPC title