Methanofullerenes
The present disclosure relates to novel methanofullerene derivatives, negative-type photoresist compositions prepared therefrom and methods of using them. The derivatives, their photoresist compositions and the methods are ideal for fine pattern processing using, for example, ultraviolet radiation, beyond extreme ultraviolet radiation, extreme ultraviolet radiation, X-rays and charged particle rays.
1. A methanofullerene comprising the general formula:
wherein x is 10-48, y is 1-6, n is 0-1, alkyl is a branched or unbranched, substituted or unsubstituted divalent alkyl chain of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, aryl is a substituted or unsubstituted divalent phenyl group, heteroaromatic group, or fused aromatic or fused heteroaromatic group, and at least one R is a photoacid labile group comprising —C═O—OR′, wherein OR′ is t-alkoxy, cycloketal, acetal, oxy-vinyl or t-butoxy.
2. The methanofullerene of claim 1 , wherein the divalent alkyl chain comprises a methylene, ethylene or 1,3-propylene group.
3. The methanofullerene of claim 1 , wherein at least one R is tert-butyl carbonate group.
4. The methanofullerene of claim 1 , wherein the photoacid labile group is chosen from an alkoxycarbonyl group or a vinyl ether group.
5. A negative-tone photoresist composition comprising:
a. At least one methanofullerene comprising the general formula:
wherein x is 10-48, y is 1-6, n is 0-1, alkyl is a branched or unbranched, substituted or unsubstituted divalent alkyl chain of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, aryl is a substituted or unsubstituted divalent phenyl group, heteroaromatic group, or fused aromatic or fused heteroaromatic group, and at least one R is a photoacid labile group comprising —C═O—OR′, wherein OR′ is t-alkoxy, cycloketal, acetal, oxy-vinyl or t-butoxy,
b. at least one photo acid generator,
c. at least one crosslinker, and
d. at least one solvent,
wherein the crosslinker crosslinks at least with the methanofullerene when processed.
6. The photoresist composition of claim 5 , wherein the divalent alkyl comprises a methylene, ethylene or 1,3-propylene group.
7. The photoresist composition of claim 5 , wherein at least one R is a tert-butyl carbonate group.
8. The photoresist composition of claim 5 , wherein the photoacid labile group is an alkoxycarbonyl group or a vinyl ether group.
9. The photoresist composition of claim 5 , wherein the at least one photoacid generator comprises an onium salt compounds, a sulfone imide compound, a halogen-containing compound, a sulfone compound, a sulfonate ester compound, a quinine-diazide compound, or a diazomethane compounds.
10. The photoresist composition of claim 9 , wherein the at least one photoacid generator comprises a triphenylsulfonium salt.
11. The photoresist composition of claim 5 , further comprising a novolac, a polyhydroxystyrene, a polyacrylate, or a maleic anhydride ester-acid polymer crosslinking additive.
12. The photoresist composition of claim 5 , wherein the at least one crosslinker comprises an acid sensitive monomer or polymer.
13. The photoresist composition of claim 12 , wherein the crosslinker comprises at least one of a glycidyl ether, glycidyl ester, glycidyl amine, a methoxymethyl group, an ethoxy methyl group, a butoxymethyl group, a benzyloxymethyl group, dimethylamino methyl group, diethylamino methyl group, a dibutoxymethyl group, a dimethylol amino methyl group, diethylol amino methyl group, a dibutylol amino methyl group, a morpholino methyl group, acetoxymethyl group, benzyloxy methyl group, formyl group, acetyl group, vinyl group or an isopropenyl group.
14. The photoresist composition of claim 12 , wherein the crosslinker comprises one or more glycidyl ether groups attached to a novolac resin.
15. The photoresist composition of claim 5 , wherein the solvent comprises esters, ethers, ether-esters, ketones, keto-esters, hydrocarbons, aromatics, and halogenated solvents.
16. The photoresist of claim 5 , further comprising at least one methanofullerene comprising the general formula:
C 2x (>C—(COO—(CH 2 CH 2 —O) a —R) 2 ) y
wherein x is 10-48, y is 1-6, a is 1-10 and R is H or an acid labile group and wherein the —CH 2 CH 2 —O— may be optionally substituted with fluorine atoms.
17. A method of forming a patterned resist layer on a substrate comprising the steps of:
a. providing a substrate,
b. applying the photoresist compositions of claim 5 , to a desired wet thickness,
c. heating the coated substrate to remove a majority of the solvent to obtain a desired thickness,
d. imagewise exposing the coating to actinic radiation,
e. removing the unexposed areas of the coating, and
f. optionally heating the remaining coating.
18. The method of claim 17 , further comprising the step of heating the imagewise exposed coating prior to removing the unexposed areas of the coating.
19. The method of claim 17 , wherein the unexposed areas are removed by treating with an organic solvent composition.
20. The method of claim 17 , wherein the actinic radiation is ultraviolet or electron beam.