Compositions and processes for photolithography
View Patent ↗Topcoat layer compositions are provided that are applied above a photoresist composition. The compositions find particular applicability to immersion lithography processing.
1. A composition suitable for use in forming a topcoat layer over a layer of photoresist, the composition comprising:
a matrix resin comprising one or more acidic functional groups;
an additive resin that is different from the matrix resin, the additive resin comprising:
as polymerized units a first monomer of the formula (I):
wherein R 1 is hydrogen or a C1 to C6 optionally substituted alkyl or fluoroalkyl group, R 2 is an optionally substituted cycloalkyl or branched alkyl group, R 3 is an optionally substituted alkylene group and R 4 and R 5 are independently C1 to C4 fluoroalkyl groups; and
as polymerized units a second monomer comprising one or more photoacid-labile groups, wherein the second monomer is of the formula (II):
wherein R 1 is, independent of R 1 of the first monomer, hydrogen or a C1 to C6 optionally substituted alkyl or fluoroalkyl group; and R 8 is an acid-labile group;
wherein the additive resin has a lower surface energy than a surface energy of the matrix resin; and
a mixture of solvents comprising 4-methyl-2-pentanol, isopentyl ether and dipropylene glycol monomethyl ether.
2. The composition of claim 1 , wherein R 2 is an optionally substituted C3 to C6 isoalkyl group.
3. The composition of claim 1 , wherein R 2 is an optionally substituted cycloalkyl group.
4. The composition of claim 1 , wherein the acidic functional group of the matrix resin is a strong acidic functional group.
5. The composition of claim 1 , wherein: the 4-methyl-2-pentanol solvent is present in an amount of from 30 to 80 wt % based on the solvent mixture; the isopentyl ether solvent is present in an amount of from 10 to 70 wt % based on the solvent mixture; and the dipropylene glycol monomethyl ether solvent is present in an amount of from 3 to 15 wt % based on the solvent mixture.
6. A coated substrate, comprising:
a photoresist layer on a substrate;
a topcoat layer on the photoresist layer, wherein the topcoat layer comprises:
a matrix resin comprising one or more acidic functional groups; and
an additive resin that is different from the matrix resin, the additive resin comprising:
as polymerized units a first monomer of the formula (I):
wherein R 1 is hydrogen or a C1 to C6 optionally substituted alkyl or fluoroalkyl group, R 2 is an optionally substituted cycloalkyl or branched alkyl group, R 3 is an optionally substituted alkylene group and R 4 and R 5 are independently C1 to C4 fluoroalkyl groups; and
as polymerized units a second monomer comprising one or more photoacid-labile groups, wherein the second monomer is of the formula (II):
wherein R 1 is, independent of R 1 of the first monomer, hydrogen or a C1 to C6 optionally substituted alkyl or fluoroalkyl group; and R 8 is an acid-labile group;
wherein the additive resin has a lower surface energy than a surface energy of the matrix resin; and
a mixture of solvents comprising 4-methyl-2-pentanol, isopentyl ether and dipropylene glycol monomethyl ether.
7. A method of processing a photoresist composition, comprising:
(a) applying a photoresist composition over a substrate to form a photoresist layer;
(b) applying over the photoresist layer a topcoat composition, the composition comprising:
a matrix resin comprising one or more acidic functional groups; and
an additive resin that is different from the matrix resin, the additive resin comprising:
as polymerized units a first monomer of the formula (I):
wherein R 1 is hydrogen or a C1 to C6 optionally substituted alkyl or fluoroalkyl group, R 2 is an optionally substituted cycloalkyl or branched alkyl group, R 3 is an optionally substituted alkylene group and R 4 and R 5 are independently C1 to C4 fluoroalkyl groups; and
as polymerized units a second monomer comprising one or more photoacid-labile groups, wherein the second monomer is of the formula (II):
wherein R 1 is, independent of R 1 of the first monomer, hydrogen or a C1 to C6 optionally substituted alkyl or fluoroalkyl group; and R 8 is an acid-labile group;
wherein the additive resin has a lower surface energy than a surface energy of the matrix resin; and
a mixture of solvents comprising 4-methyl-2-pentanol, isopentyl ether and dipropylene glycol monomethyl ether; and
(c) exposing the photoresist layer to actinic radiation.
8. The method of claim 7 , wherein the acidic functional group of the matrix resin is a strong acidic functional group.
9. The method of claim 7 , wherein: the 4-methyl-2-pentanol solvent is present in an amount of from 30 to 80 wt % based on the solvent mixture; the isopentyl ether solvent is present in an amount of from 10 to 70 wt % based on the solvent mixture; and the dipropylene glycol monomethyl ether solvent is present in an amount of from 3 to 15 wt % based on the solvent mixture.