EUV mask blank and method of making EUV mask blank

Patent metadata

Field	Value
Publication number	US-11815804-B2
Application number	US-202117481673-A
Country	US
Kind code	B2
Filing date	Sep 22, 2021
Priority date	Apr 22, 2021
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

An extreme ultraviolet mask including a substrate, a reflective multilayer stack on the substrate and a capping layer on the reflective multilayer stack is provided. The reflective multilayer stack is treated prior to formation of the capping layer on the reflective multilayer stack. The capping layer is formed by an ion-assisted ion beam deposition or an ion-assisted sputtering process.

First claim

What is claimed is:

1. An extreme ultraviolet (EUV) mask, comprising:
a substrate;
a pretreated reflective multilayer stack on the substrate; and
an amorphous capping layer of a capping layer material on the pretreated reflective multilayer stack.

2. The EUV mask of claim 1 , wherein the pretreated reflective multilayer stack is plasma pretreated.

3. The EUV mask of claim 1 , wherein the pretreated reflective multilayer stack is pretreated by exposure to pretreatment gas.

4. The EUV mask of claim 3 , wherein the pretreatment gas includes nitrogen, oxygen or a combination of nitrogen and oxygen.

5. The EUV mask of claim 1 , wherein the formed amorphous capping layer is formed by an ion-assisted deposition of the capping layer material.

6. The EUV mask of claim 1 , further comprising a diffusion prevention layer between the reflective multilayer stack and the capping layer.

7. The EUV mask of claim 1 , wherein the pretreated reflective multilayer stack includes an oxidized silicon top layer.

8. The EUV mask of claim 1 , wherein the pretreated reflective multilayer stack includes the reflective multilayer stack after exposure to a nitrogen-containing gas.

9. The EUV mask of claim 1 , further comprising a patterned absorber layer in contact with the amorphous capping layer.

10. A method of forming an extreme ultraviolet (EUV) mask, comprising:
forming a reflective multilayer stack on a substrate;
plasma treating a top layer of the reflective multilayer stack;
depositing a capping layer on the plasma treated reflective multilayer stack by an ion-assisted deposition of a capping layer material;
depositing an absorber layer on the capping layer;
forming patterned hard mask layer on the absorber layer; and
etching the absorber layer to form a plurality of openings therein using the patterned hard mask layer as an etch mask, the plurality of openings exposing a surface of the capping layer.

11. The method of claim 10 , wherein the depositing the capping layer includes depositing a capping layer of an amorphous capping layer material.

12. The method of claim 10 , wherein the depositing a capping layer on the plasma treated reflective multilayer stack is carried out at a temperature below about 150° C.

13. The method of claim 10 , wherein the depositing a capping layer on the plasma treated reflective multilayer stack is carried out at a voltage that is less than 50% of the voltage utilized by the ion beam deposition.

14. The method of claim 10 , wherein the plasma treating utilizes an argon-containing gas.

15. The method of claim 10 further comprising altering a surface of the capping layer prior to depositing the absorber layer on the capping layer, the altering including one or more of plasma treating the surface of the capping layer, exposing the surface of the capping layer to an oxygen-containing gas or exposing the surface of the capping layer to a nitrogen-containing gas.

16. A method of forming an extreme ultraviolet (EUV) mask, comprising:
forming a reflective multilayer stack on a substrate;
exposing a top layer of the reflective multilayer stack to a treatment gas;
depositing, by an ion-assisted deposition of a capping layer material, an amorphous capping layer on the top layer of the reflective multilayer stack exposed to the treatment gas;
depositing an absorber layer over the capping layer;
forming a hard mask layer on the absorber layer;
etching the hard mask layer to form a patterned hard mask layer; and
etching the absorber layer to form a plurality of openings therein using the patterned hard mask layer as an etch mask, the plurality of openings exposing a surface of the capping layer.

17. The method of claim 16 , wherein the exposing a top layer of the reflective multilayer stack to a treatment gas includes exposing a top layer of the reflective multilayer stack to an oxygen-containing gas or a nitrogen-containing gas.

18. The method of claim 16 , wherein the capping layer comprises ruthenium (Ru), iridium (Ir), rhodium (Rh), platinum (Pt), palladium (Pd), osmium (Os), rhenium (Re), vanadium (V), tantalum (Ta), hafnium (Hf), tungsten (W), molybdenum (Mo), zirconium (Zr), manganese (Mn), technetium (Tc), titanium (Ti) or alloys thereof.

19. The method of claim 16 , further comprising oxidizing a portion of the top layer of the reflective multilayer stack.

20. The method of claim 16 , wherein the exposing a top layer of the reflective multilayer stack to a treatment gas is carried out at a temperature below about 150° C.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Lin Ping-Hsun
• Hsu Pei-Cheng
• Yu Ching-Fang
• Lien Ta-Cheng
• Chen Chia-Jen
• Lee Hsin-Chang

Classifications

• G03F1/24 Primary

  Reflection masks; Preparation thereof · CPC title

• G03F1/52

  Reflectors · CPC title

• G03F1/48

  Protective coatings · CPC title