Underlayer film-forming composition and pattern forming process
In lithography, a composition comprising a novolak resin comprising recurring units derived from a naphtholphthalein is used to form a photoresist underlayer film. The underlayer film is strippable in alkaline water, without causing damage to ion-implanted Si substrates or SiO 2 substrates.
1. A photoresist underlayer film-forming composition for use in lithography, comprising a novolak resin comprising recurring units having the general formula (1) and a crosslinker:
wherein R 1 and R 2 are independently hydrogen, an acid labile group, glycidyl group, or a straight, branched or cyclic C 1 -C 10 alkyl, acyl or alkoxycarbonyl,
R 3 , R 4 and R 6 are independently hydrogen, or a straight, branched or cyclic C 1 -C 10 alkyl, C 2 -C 10 alkenyl, or C 6 -C 10 aryl group, which may have a hydroxyl, alkoxy, acyloxy, ether or sulfide moiety, or a halogen atom, hydroxyl group or C 1 -C 4 alkoxy group,
R 5 is hydrogen, or a straight, branched or cyclic C 1 -C 6 alkyl, a straight, branched or cyclic C 2 -C 10 alkenyl, or C 6 -C 12 aryl group, which may have a hydroxyl, alkoxy, ether, thioether, carboxyl, alkoxycarbonyl, acyloxy, —COOR or —OR moiety, wherein R is a lactone ring, acid labile group, or -R′-COOR″, wherein R′ is a single bond or alkylene group, and R″ is an acid labile group,
m, n, p, q and r each are 1 or 2.
2. The underlayer film-forming composition of claim 1 , further comprising an organic solvent.
3. The underlayer film-forming composition of claim 2 , further comprising an acid generator.
4. The underlayer film-forming composition of claim 3 wherein the acid generator is one capable of generating acid by pyrolysis.
5. The underlayer film-forming composition of claim 1 wherein the crosslinker is selected from the group consisting of melamine compounds, guanamine compounds, glycoluril compounds and urea compounds having substituted thereon at least one group selected from among methylol, alkoxymethyl and acyloxymethyl groups, epoxy compounds, isocyanate compounds, azide compounds, and compounds having an alkenyl ether group.
6. A process for forming a pattern in a substrate by lithography, comprising the steps of
applying the underlayer film-forming composition of claim 1 onto a substrate to form an underlayer film,
forming a photoresist film on the underlayer film,
forming a photoresist pattern via exposure and development, and
processing the underlayer film and the substrate with the photoresist pattern serving as mask.
7. The pattern forming process of claim 6 , further comprising the step of stripping the underlayer film in alkaline water before or after the step of processing the substrate.
8. The pattern forming process of claim 7 wherein the alkaline water contains 1 to 99% by weight of at least one member selected from the group consisting of ammonia, ammonia hydrogen peroxide water, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, choline hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, DBU, DBN, hydroxylamine, 1-butyl-1-methylpyrrolidinium hydroxide, 1-propyl-1-methylpyrrolidinium hydroxide, 1-butyl-1-methylpiperidinium hydroxide, 1-propyl-1-methylpiperidinium hydroxide, mepiquathydroxide, trimethylsulfonium hydroxide, hydrazines, ethylenediamines, and guanidines.
9. A process for forming a pattern in a substrate by lithography, comprising the steps of
applying the underlayer film-forming composition of claim 1 onto a substrate to form an underlayer film,
forming a photoresist film on the underlayer film,
forming a photoresist pattern via exposure and development,
processing the underlayer film with the photoresist pattern serving as mask, and
implanting ions into the substrate.
10. The pattern forming process of claim 9 , further comprising the step of stripping the underlayer film in alkaline water after the ion implantation step.
11. The pattern forming process of claim 9 , further comprising the step of stripping the underlayer film in alkaline water at pH 9 or higher.
12. A process for forming a pattern in a substrate by lithography, comprising the steps of
applying the underlayer film-forming composition of claim 1 onto a substrate to form an underlayer film,
forming a silicon-containing intermediate film on the underlayer film,
forming a photoresist film on the intermediate film,
forming a photoresist pattern via exposure and development,
processing the intermediate film with the photoresist pattern serving as mask,
processing the underlayer film with the intermediate film serving as mask, and
processing the substrate with the underlayer film serving as mask.
13. A process for forming a pattern in a substrate by lithography, comprising the steps of
applying the underlayer film-forming composition of claim 1 onto a substrate to form an underlayer film,
forming a silicon-containing intermediate film on the underlayer film,
forming a photoresist film on the intermediate film,
forming a photoresist pattern via exposure and development,
processing the intermediate film with the photoresist pattern serving as mask,
processing the underlayer film with the intermediate film serving as mask, and
implanting ions into the substrate with the underlayer film serving as mask.
14. A photoresist underlayer film-forming composition for use in lithography, consisting of a novolak resin comprising recurring units having the general formula (1), a crosslinker and an organic solvent:
wherein R 1 and R 2 are independently hydrogen, an acid labile group, glycidyl group, or a straight, branched or cyclic C 1 -C 10 alkyl, acyl or alkoxycarbonyl,
R 3 , R 4 and R 6 are independently hydrogen, or a straight, branched or cyclic C 1 -C 10 alkyl, C 2 -C 10 alkenyl, or C 6 -C 10 aryl group, which may have a hydroxyl, alkoxy, acyloxy, ether or sulfide moiety, or a halogen atom, hydroxyl group or C 1 -C 4 alkoxy group,
R 5 is hydrogen, or a straight, branched or cyclic C 1 -C 6 alkyl, a straight, branched or cyclic C 2 -C 10 alkenyl, or C 6 -C 12 aryl group, which may have a hydroxyl, alkoxy, ether, thioether, carboxyl, alkoxycarbonyl, acyloxy, —COOR or —OR moiety, wherein R is a lactone ring, acid labile group, or -R′-COOR″, wherein R′ is a single bond or alkylene group, and R″ is an acid labile group,
m, n, p, q and r each are 1 or 2.
15. The underlayer film-forming composition of claim 14 wherein the crosslinker is selected from the group consisting of melamine compounds, guanamine compounds, glycoluril compounds and urea compounds having substituted thereon at least one group selected from among methylol, alkoxymethyl and acyloxymethyl groups, epoxy compounds, isocyanate compounds, azide compounds, and compounds having an alkenyl ether group.
16. A photoresist underlayer film-forming composition for use in lithography, consisting of a novolak resin comprising recurring units having the general formula (1), an acid generator, a crosslinker and an organic solvent:
wherein R 1 and R 2 are independently hydrogen, an acid labile group, glycidyl group, or a straight, branched or cyclic C 1 -C 10 alkyl, acyl or alkoxycarbonyl,
R 3 , R 4 and R 6 are independently hydrogen, or a straight, branched or cyclic C 1 -C 10 alkyl, C 2 -C 10 alkenyl, or C 6 -C 10 aryl group, which may have a hydroxyl, alkoxy, acyloxy, ether or sulfide moiety, or a halogen atom, hydroxyl group or C 1 -C 4 alkoxy group,
R 5 is hydrogen, or a straight, branched or cyclic C 1 -C 6 alkyl, a straight, branched or cyclic C 2 -C 10 alkenyl, or C 6 -C 12 aryl group, which may have a hydroxyl, alkoxy, ether, thioether, carboxyl, alkoxycarbonyl, acyloxy, —COOR or —OR moiety, wherein R is a lactone ring, acid labile group, or -R′-COOR″, wherein R′ is a single bond or alkylene group, and R″ is an acid labile group,
m, n, p, q and r each are 1 or 2.
17. The underlayer film-forming composition of claim 16 wherein the crosslinker is selected from the group consisting of melamine compounds, guanamine compounds, glycoluril compounds and urea compounds having substituted thereon at least one group selected from among methylol, alkoxymethyl and acyloxymethyl groups, epoxy compounds, isocyanate compounds, azide compounds, and compounds having an alkenyl ether group.
18. The underlayer film-forming composition of claim 16 wherein the acid generator is one capable of generating acid by pyrolysis.