Photoresist composition for deep ultraviolet lithography
View Patent ↗The present invention relates to a photoresist composition comprising a photoacid generator and at least one polymer comprising at least one unit as described by structure 1, The invention also relates to a process for imaging the photoresist composition of the present invention, and to a process of making the polymer in the presence of an organic base.
1. A process for imaging a photoresist composition comprising the steps of:
a) forming on a substrate a photoresist coating from a photoresist composition;
b) image-wise exposing the photoresist coating;
c) postexposure baking the photoresist coating; and
d) developing the photoresist coating with an aqueous alkaline solution; and,
where the photoresist composition comprises a photoacid generator and a fluorinated polymer, where the fluorinated polymer is a reaction product of polymer containing an aliphatic monocyclic fluoroalcohol unit with at least one compound capable of functionalizing the fluoroalcohol unit with an alkyloxycarbonylalkyl group of structure—(CR 3 R 4 )p(CO)OR 5, where R 3 and R 4 are independently H, F, (C 1 -C 8 )alkyl, (C 1 -C 8 )fluoroalkyl, cycloalkyl, cyclofluoroalkyl, (CR 3 R 4 )p(CO)OR 5, R 3 and R 4 may combine to form an alkyispirocyclic or a fluoroalkylspirocyclic group, R 5 is H or an acid labile group, and p=1-4 further where the polymer containing the monocyclic fluoroalcohol unit is selected from at least one of structures I to VIII,
where Rf is a fluoroalkyl group (C 1 -C 8 ),
Ra, Rb, Rc, Re, Rg and Rh are independently alkyl and fluoroalkyl, and Ra-Re and Rg can independently be substituted with alkyl, fluoroalkyl, spirofluoroalkyl or spiroalkyl substituent, where at least one of Ra, Rb, Rc and Rd is a fluoroalkyl group,
Y is independently alkyl or fluoroalkyl spacer group (C 1 -C 8 ), and
X is independently CF 2 or O.
2. The process according to claim 1 , where the image-wise exposure wavelength is below 200 nm.
3. The process according to claim 1 , where the aqueous alkaline solution comprises tetramethylammonium hydroxide.
4. The process according to claim 1 , where the aqueous alkaline solution further comprises a surfactant.
5. The process of claim 1 , where the alkyloxycarbonylalkyl group is selected from t-butyloxycarbonylmethyl, methyl-adamantyloxycarbonylmethyl, t-amyloxycarbonylmethyl, methyl-norbornyloxycarbonylmethyl, t-butyloxycarbonylpropyl and t-butyloxycarbonyldifluorobutyl.
6. The process of claim 1 , where the acid labile group is selected from secondary and tertiary alkyls, acetals and ketals, trimethylsilyl, β-trimethylsilyl substituted alkyls, tetrahydrofuranyl, tetrahydropyranyl, substituted or unsubstituted methoxymethoxycarbonyl, and β-trialkylsilylalkyl.
7. The process of claim 1 , where the fluoroalcohol unit is further functionalized with a compound containing nonacid labile groups and/or acid labile groups.
8. The process of claim 1 , where the polymer containing an aliphatic monocyclic fluoroalcohol unit is selected from poly(1,1,2,3,3-pentafluoro-4-trifluoromethyl-4-hydroxy-1,6-heptadiene and poly(1,1,2,3,3-pentafluoro-4-trifluoroalkyl-4-hydroxy-1,6-heptadiene).
9. The process of claim 1 , where the photoresist composition further comprises a polymer with multicyclic units in the polymer backbone.
10. The process of claim 9 , where the polymer with the multicyclic unit is poly(1,1,2,3,3-pentafluoro-4-trifluoromethyl-4-hydroxy-1,6-heptadiene) protected with an alkyloxycarbonylalkyl group.
11. The process of claim 1 , where the photoresist composition further comprises a dissolution inhibitor.
12. The process of claim 1 , where the photoresist composition further comprises a base or a photobase.
13. The process of claim 1 , where the photoresist further comprises secondary polymers.
14. The process of claim 12 , where the photoresist further comprises secondary polymers.
15. The process of claim 1 , where the photoacid generator is selected from diazonium salts, iodonium salts, sulfonium salts, triazines, oxazoles, oxadiazoles, thiazoles, substituted 2-pyrones, phenolic sulfonic esters and mixtures thereof.
16. The process of claim 1 , where the polymer containing an aliphatic monocyclic fluoroalcohol unit is selected from at least one of the structures,
where, Rf is a fluoroalkyl group (C 1 -C 8 ),
Z is independently CF 2 , C(C n F 2n+1) ) 2 , C(C n F 2n+1) ) (C n H 2n+1) ), n=1-12,
Y is independently alkyl or fluoroalkyl spacer group (C 1 -C 8 ), and
X is independently CF 2 or O.
17. The process of claim 16 , where the photoresist composition further comprises a base or a photobase.
18. The process of claim 17 , where the photoresist composition further comprises a secondary polymer.
19. The process of claim 16 , where the photoresist composition further comprises a secondary polymer.