Resist underlayer film composition, process for forming resist underlayer film, patterning process and fullerene derivative

1. A resist underlayer film composition of a multilayer resist film used in lithography including (A) a fullerene derivative having a carboxyl group protected by a thermally labile group, (B) an organic solvent, and (C) a resin containing an aromatic ring,

wherein the fullerene derivative has n partial structures represented by formula (I):

wherein:

R 1 represents a thermally labile group;

R 2 represents a hydrogen atom, a cyano group, —COOR 3 , a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 16 carbon atoms, a heteroaryl group having 4 to 16 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, R 2 optionally containing a carbonyl group, an ether group, a ester group, a cyano group, a carboxyl group or a hydroxyl group, where R 3 represents a hydrogen atom, R 1 , or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms;

C F represents a carbon atom constituting a fullerene skeleton of the fullerene derivative; and

n represents an integer of 1 to 30;

wherein the resin (C) containing an aromatic ring comprises at least a compound (C1) obtained by a polycondensation reaction between a compound represented by the following general formula (2) and a compound represented by the following general formula (3) under an acid condition,

wherein:

each R 4 independently represents a hydrogen atom or a hydrocarbon group having 6 to 20 carbon atoms;

each R 5 independently represents a benzene ring or a naphthalene ring;

m1 to m4 satisfy 1≦m1+m2≦2, and 1≦m3+m4≦2; and

each n1 and n2 is 0 or 1,

A-CHO  (3),

wherein:

A represents:

a hydrogen atom;

a saturated or an unsaturated linear, branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms; or

an aromatic hydrocarbon group having 6 to 20 carbon atoms,

A optionally containing an ether group, a nitro group, a hydroxyl group, or a chloro group.

2. The resist underlayer film composition according to claim 1 , wherein the fullerene derivative has n partial structures represented by the following general formula (1a),

wherein:

R 1a represents a substituted or an unsubstituted linear or cyclic tertiary alkyl group having 4 to 30 carbon atoms, optionally containing an unsaturated bond or an aromatic ring;

R 2a represents a hydrogen atom, a cyano group, —COOR 3a , a methyl group, an ethyl group, an acetyl group, a phenyl group, a naphthyl group, a furyl group, a benzoyl group or a naphthoyl group, R 3a represents a hydrogen atom, R 1a , or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms;

C F represents a carbon atom constituting a fullerene skeleton of the fullerene derivative; and

n represents an integer of 1 to 30.

3. The resist underlayer film composition according to claim 1 , wherein the resist underlayer film composition includes a mixture of two or more of the fullerene derivatives having a different n value from each other and the n value of a fullerene derivative having a highest presence ratio is an integer of 3 to 10.

4. The resist underlayer film composition according to claim 2 , wherein the resist underlayer film composition includes a mixture of two or more of the fullerene derivatives having a different n value from each other and the n value of a fullerene derivative having a highest presence ratio is an integer of 3 to 10.

5. The resist underlayer film composition according to claim 1 , further comprising at least one selected from the group consisting of:

(D) a compound containing a phenolic hydroxyl group,

(E) an acid generator,

(F) a crosslinker, and

(G) a surfactant.

6. A process for forming a resist underlayer film of a multilayer resist film used in lithography, comprising:

coating the resist underlayer film composition according to claim 1 on a substrate; and

heat treating the resist underlayer film composition at a temperature of 200° C. or more and 600° C. or less for 10 to 600 sec to be cured, thereby forming the resist underlayer film.

7. A process for forming a resist underlayer film of a multilayer resist film used in lithography, comprising:

coating the resist underlayer film composition according to claim 1 on a substrate; and

baking the resist underlayer film composition in an atmosphere with an oxygen concentration of 0.1% or more and 21% or less to be cured, thereby forming the resist underlayer film.

8. A patterning process for forming a pattern on a substrate by lithography, comprising the steps of:

forming a resist underlayer film on the substrate using the resist underlayer film composition according to claim 1 ;

forming a resist intermediate layer film on the resist underlayer film using a resist intermediate layer film composition containing a silicon atom;

forming a resist upper layer film on the resist intermediate layer film using a resist upper layer film composition composed of a photoresist composition to form a multilayer resist film;

conducting exposure of a pattern circuit region of the resist upper layer film and then developing it with a developer to form a resist pattern in the resist upper layer film;

etching the resist intermediate layer film using the pattern-formed resist upper layer film as a mask;

etching the resist underlayer film using the pattern-formed resist intermediate layer film as a mask; and

etching the substrate using the pattern-formed resist underlayer film as a mask to form a pattern on the substrate.

9. The patterning process according to claim 8 , wherein etching of the resist underlayer film using the pattern-formed resist intermediate layer film as a mask is performed using an etching gas mainly comprising an oxygen gas or a hydrogen gas.

10. A patterning process for forming a pattern on a substrate by lithography, comprising the steps of:

forming a resist underlayer film on the substrate using the resist underlayer film composition according to claim 1 ;

forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film;

forming a resist upper layer film on the inorganic hard mask intermediate film using a resist upper layer film composition composed of a photoresist composition;

conducting exposure of a pattern circuit region of the resist upper layer film and then developing it with a developer to form a resist pattern in the resist upper layer film;

etching the inorganic hard mask intermediate film using the obtained resist pattern as an etching mask;

etching the resist underlayer film using the obtained inorganic hard mask intermediate film pattern as an etching mask; and

etching the substrate using the obtained resist underlayer film pattern as an etching mask to form a pattern on the substrate.

11. A patterning process for forming a pattern on a substrate by lithography, comprising the steps of:

forming a resist underlayer film on the substrate using the resist underlayer film composition according to claim 1 ;

forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film;

forming an organic antireflection film on the inorganic hard mask intermediate film;

forming a resist upper layer film on the organic antireflection film using a resist upper layer film composition composed of a photoresist composition;

conducting exposure of a pattern circuit region of the resist upper layer film and then developing it with a developer to form a resist pattern in the resist upper layer film;

etching the organic antireflection film and the inorganic hard mask intermediate film using the obtained resist pattern as an etching mask;

etching the resist underlayer film using the obtained inorganic hard mask intermediate film pattern as an etching mask; and

etching the substrate using the obtained resist underlayer film pattern as an etching mask to form a pattern on the substrate.

12. The patterning process according to claim 10 , wherein the inorganic hard mask intermediate film is formed by a CVD method or an ALD method.

13. The patterning process according to claim 11 , wherein the inorganic hard mask intermediate film is formed by a CVD method or an ALD method.