Pattern-forming method, resist underlayer film, and composition for forming resist underlayer film
A pattern-forming method includes: (1) a resist underlayer film-forming step of providing a resist underlayer film on an upper face side of a substrate by coating a resist underlayer film-forming composition containing a resin having a phenolic hydroxyl group; (2) a resist pattern-forming step of forming a resist pattern on an upper face side of the resist underlayer film; (3) a pattern-forming step of dry etching at least the resist underlayer film and the substrate, with the aid of the resist pattern as a mask to form a pattern on the substrate; and (4) a resist underlayer film-removing step of removing the resist underlayer film on the substrate with a basic solution, in the order of (1) to (4).
1. A pattern-forming method sequentially comprising the steps of:
(1) providing a resist underlayer film on an upper face side of a substrate by coating a resist underlayer film-forming composition containing a resin having phenolic structures, each of the phenolic structures has a phenolic hydroxyl group;
(2) forming a resist pattern on an upper face side of the resist underlayer film;
(3) dry etching at least the resist underlayer film and the substrate, with the aid of the resist pattern as a mask to form a pattern on the substrate; and
(4) removing the resist underlayer film on the substrate with a basic solution,
wherein at least a part of the phenolic structures of the resin in the step of providing a resist underlayer film are modified to quinone structures which replace the at least a part of the phenolic structures, and
wherein the resin is heated at a temperature of at least 200° C. under an ambient oxygen concentration of no less than 5% by volume to modify the at least a part of the phenolic structures.
2. The pattern-forming method according to claim 1 , wherein the method further comprises the step of
(1′) providing an intermediate layer on an upper face side of the resist underlayer film, after the step of providing a resist underlayer film (1) and before the step of forming a resist pattern (2), and wherein
the intermediate layer is also dry etched in the step of forming a pattern (3).
3. The pattern-forming method according to claim 1 , wherein the resist underlayer film-forming composition comprises a crosslinking agent at a content with respect to 100 parts by mass of the resin of no less than 0 parts by mass and no greater than 3 parts by mass.
4. The pattern-forming method according to claim 1 , wherein the resin is heated at a temperature of 200° C. to 300° C. under an ambient oxygen concentration of no less than 5% by volume to modify the at least a part of the phenolic structures.
5. The pattern-forming method according to claim 1 , wherein the basic solution includes tetramethylammonium hydroxide or tetraethylammonium hydroxide.
6. A resist underlayer film provided by coating a resist underlayer film-forming composition comprising a resin having phenolic structures, each of the phenolic structures has a phenolic hydroxyl group, the resist underlayer film being hardly soluble in an organic solvent and soluble in a basic solution,
wherein at least a part of the phenolic structures of the resin are modified to quinone structures which replace the at least a part of the phenolic structures, and
wherein the resin is heated at a temperature of at least 200° C. under an ambient oxygen concentration of no less than 5% by volume to modify the at least a part of the phenolic structures.
7. The resist underlayer film according to claim 6 , wherein the resin is heated at a temperature of 200° C. to 300° C. under an ambient oxygen concentration of no less than 5% by volume to modify the at least a part of the phenolic structures.
8. A resist underlayer film-forming composition that is for use in a pattern-forming method sequentially comprising:
(1) providing a resist underlayer film on an upper face side of a substrate by coating a resist underlayer film-forming composition;
(2) forming a resist pattern on an upper face side of the resist underlayer film;
(3) dry etching at least the resist underlayer film and the substrate, with the aid of the resist pattern as a mask to form a pattern on the substrate; and
(4) removing the resist underlayer film on the substrate with a basic solution, the resist underlayer film-forming composition comprising a resin having phenolic structures, each of the phenolic structures has a phenolic hydroxyl group,
wherein at least a part of the phenolic structures of the resin in the step of providing a resist underlayer film are modified to quinone structures which replace the at least a part of the phenolic structures, and
wherein the resin is heated at a temperature of at least 200° C. under an ambient oxygen concentration of no less than 5% by volume to modify the at least a part of the phenolic structures.
9. The resist underlayer film-forming composition according to claim 8 , wherein the resin is heated at a temperature of 200° C. to 300° C. under an ambient oxygen concentration of no less than 5% by volume to modify the at least a part of the phenolic structures.
10. The resist underlayer film-forming composition according to claim 8 , wherein the basic solution includes tetramethylammonium hydroxide or tetraethylammonium hydroxide.