Pattern formation method and photosensitive hard mask

Patent metadata

Field	Value
Publication number	US-12379653-B2
Application number	US-202217861566-A
Country	US
Kind code	B2
Filing date	Jul 11, 2022
Priority date	Jul 13, 2021
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

A pattern formation method includes: forming a photosensitive hard mask made of a transition metal oxide film on a surface of a substrate; exposing the photosensitive hard mask to EUV light in a desired pattern; causing a state change in an exposed region by heat generated during exposure; and selectively removing either a region where the state change has occurred or a region where the state change has not occurred.

First claim

What is claimed is:

1. A pattern formation method, comprising:
forming a photosensitive hard mask made of a transition metal oxide film on a surface of a substrate;
exposing the photosensitive hard mask to EUV light in a desired pattern;
causing a state change in an exposed region by heat generated during exposure; and
selectively removing either a region where the state change has occurred or a region where the state change has not occurred,
wherein a thickness t of the transition metal oxide film constituting the photosensitive hard mask is in a range of λ≤t≤3λ, where λ is an extinction length of the EUV light used for the exposure.

2. The pattern formation method of claim 1 , wherein the state change is a phase transition or a composition change.

3. The pattern formation method of claim 2 , wherein a transition metal oxide constituting the transition metal oxide film is a tetravalent transition metal oxide.

4. The pattern formation method of claim 3 , wherein the tetravalent transition metal oxide is HfO 2 or ZrO 2 .

5. The pattern formation method of claim 4 , wherein the transition metal oxide film is an amorphous phase HfO 2 film, and the exposed region is configured to undergo a phase transition to a crystalline phase by being heated to a crystallization temperature or higher.

6. The pattern formation method of claim 2 , wherein a transition metal oxide constituting the transition metal oxide film is a low-melting-point polyvalent oxide.

7. The pattern formation method of claim 6 , wherein the low-melting-point polyvalent oxide is WO x , MoO x , and VO x .

8. The pattern formation method of claim 7 , wherein the transition metal oxide film is an amorphous phase MoO x film or a crystalline phase MoO x film, the exposed region is heated to a crystallization temperature or higher to undergo a phase transition to a crystalline phase when the amorphous phase MoO x film is used, and the exposed region is heated to a temperature higher than a melting point thereof and rapidly cooled to undergo the phase transition to an amorphous phase when the crystalline phase MoO x film is used.

9. The pattern formation method of claim 1 , wherein the selectively removing is performed by a dry etching or a wet etching.

10. A pattern formation method, comprising:
forming a photosensitive hard mask made of a transition metal oxide film on a surface of a substrate on which a film to be processed and a hard mask are formed;
exposing the photosensitive hard mask to EUV light in a desired pattern;
causing a state change in an exposed region by heat generated during exposure;
forming a pattern on the photosensitive hard mask by selectively removing either a region where the state change has occurred or a region where the state change has not occurred;
transferring the pattern of the photosensitive hard mask to the hard mask; and
forming a pattern on the film to be processed by etching the film to be processed by using the hard mask to which the pattern is transferred as a mask,
wherein a thickness t of the transition metal oxide film constituting the photosensitive hard mask is in a range of λ≤t≤3λ, where λ is an extinction length of the EUV light used for the exposure.

11. A photosensitive hard mask exposed and developed by EUV light in a desired pattern to form a pattern,
wherein the photosensitive hard mask is made of a transition metal oxide film, and is configured so that when exposed to the EUV light, a state change occurs in an exposed region due to heat generated during exposure, the photosensitive hard mask having the pattern formed by selectively removing either a region where the state change has occurred or a region where the state change has not occurred, and
wherein a thickness t of the transition metal oxide film constituting the photosensitive hard mask is in a range of λ≤t≤3λ, where λ is an extinction length of the EUV light used for the exposure.

12. The photosensitive hard mask of claim 11 , wherein the state change is a phase transition or a composition change.

13. The photosensitive hard mask of claim 12 , wherein a transition metal oxide constituting the transition metal oxide film is a tetravalent transition metal oxide.

14. The photosensitive hard mask of claim 13 , wherein the tetravalent transition metal oxide is HfO 2 or ZrO 2 .

15. The photosensitive hard mask of claim 14 , wherein the transition metal oxide film is an amorphous phase HfO 2 film, and the exposed region is configured to undergo a phase transition to a crystalline phase by being heated to a crystallization temperature or higher.

16. The photosensitive hard mask of claim 12 , wherein a transition metal oxide constituting the transition metal oxide film is a low-melting-point polyvalent oxide.

17. The photosensitive hard mask of claim 16 , wherein the low-melting-point polyvalent oxide is WO x , MoO x , and VO x .

18. The photosensitive hard mask of claim 17 , wherein the transition metal oxide film is an amorphous phase MoO x film or a crystalline phase MoO x film, the exposed region is heated to a crystallization temperature or higher to undergo a phase transition to a crystalline phase when the amorphous phase MoO x film is used, and the exposed region is heated to a temperature higher than a melting point thereof and rapidly cooled to undergo the phase transition to an amorphous phase when the crystalline phase MoO x film is used.

Assignees

• Tokyo Electron Ltd

Inventors

• Nakabayashi Hajime
• Yamaji Tomohito
• Yamada Kazuki
• Asako Ryuichi

Classifications

• H10P76/4085 Primary

  characterised by the processes involved to create the masks · CPC title

• H10P76/405 Primary

  characterised by their composition, e.g. multilayer masks · CPC title

• G03F7/11

  having cover layers or intermediate layers, e.g. subbing layers {(G03F7/091 - G03F7/093, B41N3/03 take precedence)} · CPC title

• G03F7/0042

  with inorganic or organometallic light-sensitive compounds not otherwise provided for, e.g. inorganic resists (G03F7/075 takes precedence) · CPC title

• G03F7/094

  Multilayer resist systems, e.g. planarising layers · CPC title