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 and substantially immiscible with 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 a dialkyl glycol monoalkyl ether effective to achieve phase separation of the additive resin from the matrix resin during spin-coating.
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 mixture of solvents further comprises: an alcohol; and an alkyl ether and/or an alkane.
6. The composition of claim 1 , wherein the dialkyl glycol monoalkyl ether is dipropylene glycol monomethyl ether.
7. The composition of claim 1 , wherein the mixture of solvents comprises: a primary solvent; a thinner solvent; and an additive solvent having a boiling point higher than that of the primary solvent and the thinner solvent, wherein the dialkyl glycol monoalkyl ether is the additive solvent.
8. The composition of claim 7 , wherein the primary solvent has a boiling point of from 120 to 140° C. and the thinner solvent has a boiling point of from 140 to 180° C.
9. The composition of claim 7 , wherein: the primary solvent is present in an amount of from 30 to 80 wt % based on the solvent mixture; the thinner solvent is present in an amount of from 10 to 70 wt % based on the solvent mixture; and the additive solvent is present in an amount of from 3 to 15 wt % based on the solvent mixture.
10. 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 and substantially immiscible with 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 a dialkyl glycol monoalkyl ether effective to achieve phase separation of the additive resin from the matrix resin during spin-coating; and
(c) exposing the photoresist layer to actinic radiation.
11. The method of claim 10 , wherein the acidic functional group of the matrix resin is a strong acidic functional group.
12. The method of claim 10 , wherein the mixture of solvents further comprises: an alcohol; and an alkyl ether and/or an alkane.
13. The method of claim 10 , wherein the mixture of solvents comprises: a primary solvent; a thinner solvent; and an additive solvent having a boiling point higher than that of the primary solvent and the thinner solvent, wherein the dialkyl glycol monoalkyl ether is the additive solvent.
14. The method of claim 13 , wherein the primary solvent has a boiling point of from 120 to 140° C. and the thinner solvent has a boiling point of from 140 to 180° C.
15. The method of claim 13 , wherein: the primary solvent is present in an amount of from 30 to 80 wt % based on the solvent mixture; the thinner solvent is present in an amount of from 10 to 70 wt % based on the solvent mixture; and the additive solvent is present in an amount of from 3 to 15 wt % based on the solvent mixture.