Pattern formation methods and photoresist pattern overcoat compositions
A pattern formation method, comprising: (a) providing a semiconductor substrate; (b) forming a photoresist pattern over the semiconductor substrate, wherein the photoresist pattern is formed from a photoresist composition comprising: a first polymer comprising acid labile groups; and a photoacid generator; (c) coating a pattern overcoat composition over the photoresist pattern, wherein the pattern overcoat composition comprises a second polymer and an organic solvent, wherein the organic solvent comprises one or more ester solvents, wherein the ester solvent is of the formula R 1 —C(O)O—R 2 , wherein R 1 is a C3-C6 alkyl group and R 2 is a C5-C10 alkyl group; (d) baking the coated photoresist pattern; and (e) rinsing the coated photoresist pattern with a rinsing agent to remove the second polymer. The methods find particular applicability in the manufacture of semiconductor devices.
1. A pattern formation method, comprising:
(a) providing a semiconductor substrate;
(b) forming a photoresist pattern over the semiconductor substrate, wherein the photoresist pattern is formed from a photoresist composition comprising: a first polymer comprising acid labile groups; and a photoacid generator;
(c) coating a pattern overcoat composition over the photoresist pattern, wherein the pattern overcoat composition comprises a second polymer and a plurality of organic solvents comprising one or more ester solvents and one or more monoether solvents, wherein the ester solvent is of the formula R 1 —C(O)O—R 2 , wherein R 1 is a C3-C6 alkyl group and R 2 is a C5-C10 alkyl group;
(d) baking the coated photoresist pattern; and
(e) rinsing the coated photoresist pattern with a rinsing agent to remove the second polymer.
2. The method of claim 1 , wherein the first polymer comprises a repeat unit of the following formula (III):
wherein: R 4 is hydrogen or methyl; R 5 is one or more groups chosen from hydroxyl, C1-C8 alkoxy, C5-C12 aryloxy, C2-C10 alkoxycarbonyloxy, C1-C4 alkyl, C5-C15 aryl and C6-C20 aralkyl, wherein one or more carbon hydrogens are optionally substituted with a halogen atom; b is an integer of from 1 to 5; wherein at least one R 5 is independently chosen from hydroxyl, C1-C8 alkoxy, C5-C12 aryloxy and C2-C10 alkoxycarbonyloxy.
3. The method of claim 1 , wherein the ester solvent is isoamyl isobutyrate.
4. The method of claim 1 , wherein the pattern overcoat composition further comprises an alcohol solvent.
5. The method of claim 1 , wherein the second polymer comprises a repeat unit comprising a —C(CF 3 ) 2 OH group and/or a repeat unit comprising an acid group.
6. The method of claim 1 , wherein the pattern overcoat composition is free of non-polymeric acids and non-polymeric acid generators.
7. The method of claim 1 , wherein the rinsing agent is an aqueous tetramethylammonium hydroxide solution.
8. The method of claim 1 , wherein forming the photoresist pattern comprises exposing a layer formed from the photoresist composition to EUV radiation.