Pattern formation method and photosensitive hard mask
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.
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.