Onium salts, photoacid generators, resist compositions, and patterning process
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsYouichi Ohsawa, Jun Watanabe, Satoshi Watanabe, Shigehiro Nagura
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Abstract
Onium salts of substituted phenylmethylbenzene-sulfonate anions with iodonium or sulfonium cations are novel. A chemically amplified resist composition comprising the onium salt as a photoacid generator is suited for microfabrication, especially by deep UV lithography because of many advantages including improved resolution, minimized line width variation or shape degradation even on long-term PED, minimized defect after coating, development and peeling, and improved pattern profile after development.
Claims18
An onium salt of the following general formula (1):
- wherein R1 is hydrogen or a straight, branched or cyclic alkyl group of 1 to 6 carbon atoms, R2 is hydrogen, a straight, branched or cyclic alkyl group of 1 to 6 carbon atoms or phenyl group, R3 which may be the same or different is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or substituted or unsubstituted aryl group of 6 to 14 carbon atoms, M is a sulfur or iodine atom, and “a” is equal to 3 when M is sulfur and equal to 2 when M is iodine.
A sulfonium salt of the following general formula (1a):
- wherein R1, R2 and R3 are as defined above.
A sulfonium salt of the following general formula (1a′):
- wherein R1, R2 and R3 are as defined above, G is an acid labile group having an oxygen atom attached thereto or R2O— or (R2)2N—, g is an integer of 0 to 4, h is an integer of 1 to 5, g+h=5, e is an integer of 1 to 3, f is an integer of 0 to 2, and e+f=3.
A iodonium salt of the following general formula (1b):
- wherein R1 and R2 are as defined above.
Dependencies are inferred from the claim text.