Photocrosslinkable group-containing composition for coating stepped substrate
There is provided a composition for coating a stepped substrate that has high filling properties of a pattern, and is capable of forming a coating film that does not cause degassing and heat shrinkage, and is used to form a coating film having flattening properties on the substrate. The composition for coating a stepped substrate includes a compound (C) having in the molecule a partial structure of Formula (1) (where R1 and R2 are each independently a hydrogen atom, a C1-10 alkyl group, or a C6-40 aryl group; five R3s are each independently a hydrogen atom, a hydroxy group, a C1-10 alkoxy group, a C1-10 alkyl group, a nitro group, or a halogen atom; and * is a bond site to the compound); and a solvent.
1. A photocurable composition for coating a stepped substrate, the photocurable composition capable of being photocured by light irradiation, the photocurable composition comprising
a compound (C) having in the molecule a partial structure of Formula (1):
wherein R 1 and R 2 are each independently a hydrogen atom, a C 1-10 alkyl group, or a C 6-40 aryl group, five R 3 s are each independently a hydrogen atom, a hydroxy group, a C 1-10 alkoxy group, a C 1-10 alkyl group, a nitro group, or a halogen atom, and * is a bond site to the compound, wherein the compound (C) is a reaction product of an epoxy group-containing compound (A) and a cinnamic acid (B) having the partial structure of Formula (1), and
a solvent,
wherein the photocurable composition is free of a thermal crosslinking moiety and an acid catalyst.
2. The photocurable composition for coating a stepped substrate according to claim 1 , wherein the compound (C) is the reaction product in which the mole ratio of an epoxy group of the epoxy group-containing compound (A) to the cinnamic acid (B) having the partial structure of formula (1) is 1:1 to 4:1.
3. The photocurable composition for coating a stepped substrate according to claim 1 , wherein the epoxy group-containing compound (A) is an epoxy group-containing benzene or epoxy group-containing benzene fused ring compound, an epoxy group-containing aliphatic polyether, an epoxy group-containing novolak polymer, a polyether of epoxy group-containing alicyclic hydrocarbon, or an epoxy group-containing polyester.
4. The photocurable composition for coating a stepped substrate according to claim 1 , wherein the composition is capable of forming a resist underlayer film in a lithography process for production of a semiconductor device.
5. A method of producing a coated substrate comprising steps of:
(i) applying the photocurable composition for coating a stepped substrate according to claim 1 to a stepped substrate; and
(ii) exposing the coated substrate to actinic radiation.
6. The method according to claim 5 , wherein the step (i) further includes a step (ia) of heating the coated substrate at a temperature of 70 to 400° C. for 10 seconds to 5 minutes after applying the photocurable composition for coating a stepped substrate to the substrate.
7. The method according to claim 5 , wherein the actinic radiation in the step (ii) has a wavelength of 250 nm to 350 nm.
8. The method according to claim 5 , wherein the exposure dose in the step (ii) is 500 mJ/cm 2 to 1,500 mJ/cm 2 .
9. The method according to claim 5 , wherein the stepped substrate has an open area (unpatterned area) and a pattern area of DENSE (dense) and ISO (coarse), and the aspect ratio of the pattern is 0.1 to 10.
10. The method according to claim 5 , wherein the coated substrate to be produced has a bias (difference in level of coating) between the open area and the pattern area of 1 to 50 nm.
11. A method of producing a semiconductor device comprising steps of:
forming an underlayer film on a stepped substrate from the photocurable composition for coating a stepped substrate according to claim 1 ;
forming a resist film on the underlayer film;
forming a resist pattern by irradiation with light or an electron beam and development;
etching the underlayer film through the formed resist pattern; and
processing a semiconductor substrate using the patterned underlayer film.
12. The method according to claim 11 , wherein the stepped substrate has an open area (unpatterned area) and a pattern area of DENSE (dense) and ISO (coarse), and the aspect ratio of the pattern is 0.1 to 10.
13. The method according to claim 11 , wherein the step of forming an underlayer film from the photocurable composition for coating a stepped substrate includes steps of:
(i) applying the photocurable composition for coating a stepped substrate according to claim 1 to the stepped substrate; and
(ii) exposing the coated substrate to actinic radiation.
14. The method according to claim 13 , wherein the step (i) further includes a step (ia) of heating the coated substrate at a temperature of 70 to 400° C. for 10 seconds to 5 minutes after applying the photocurable composition for coating a stepped substrate to the substrate.
15. The method according to claim 13 , wherein the actinic radiation in the step (ii) has a wavelength of 250 nm to 350 nm.
16. The method according to claim 13 , wherein the exposure dose in the step (ii) is 500 mJ/cm 2 to 1,500 mJ/cm 2 .
17. The method according to claim 11 , wherein the underlayer film formed from the photocurable composition for coating a stepped substrate has a bias between the open area and the pattern area of 1 to 50 nm.
18. A method of producing a semiconductor device comprising steps of:
forming an underlayer film on a stepped substrate from the photocurable composition for coating a stepped substrate according to claim 1 ;
forming a hard mask on the underlayer film;
forming a resist film on the hard mask;
forming a resist pattern by irradiation with light or an electron beam and development;
etching the hard mask through the formed resist pattern;
etching the underlayer film through the patterned hard mask; and
processing a semiconductor substrate through the patterned underlayer film.
19. The method according to claim 18 , wherein the stepped substrate has an open area (unpatterned area) and a pattern area of DENSE (dense) and ISO (coarse), and the aspect ratio of the pattern is 0.1 to 10.
20. The method according to claim 18 , wherein the step of forming an underlayer film from the photocurable composition for coating a stepped substrate includes steps of:
(i) applying the photocurable composition for coating a stepped substrate according to claim 1 to the stepped substrate; and
(ii) exposing the coated substrate to actinic radiation.
21. The method according to claim 20 , wherein the step (i) further includes a step (ia) of heating the coated substrate at a temperature of 70 to 400° C. for 10 seconds to 5 minutes after applying the composition for coating a stepped substrate to the substrate.
22. The method according to claim 20 , wherein the actinic radiation in the step (ii) has a wavelength of 250 nm to 350 nm.
23. The method according to claim 20 , wherein the exposure dose in the step (ii) is 500 mJ/cm 2 to 1,500 mJ/cm 2 .
24. The method according to claim 18 , wherein the underlayer film formed from the photocurable composition for coating a stepped substrate has a bias between the open area and the pattern area of 1 to 50 nm.