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US 12,275,693 B2Granted
Onium salt, chemically amplified resist composition and patterning process
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsMasayoshi Sagehashi, Takayuki Fujiwara, Masahiro Fukushima, Masaki Ohashi, Kazuhiro Katayama
Life of this patent
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Abstract
An onium salt of formula (1) and a chemically amplified resist composition comprising the same as a PAG are provided. When processed by lithography, the resist composition exhibits a high sensitivity, minimal LWR and improved CDU independent of whether it is of positive or negative tone.
Claims8
An onium salt having the formula (1):
- wherein R1 is a C1-C20 di- to tetravalent hydrocarbon group,
- R2 is a single bond or a C1-C20 divalent hydrocarbon group,
- R3 is fluorine, a C1-C10 alkoxy group, nitro group, or C1-C10 monovalent hydrocarbon group,
- Rf1 and Rf2 each are fluorine, Rf3 is trifluoromethyl, and Rf4 is hydrogen,
- L1 is —CO—O—,
- m is 1, n is 1, k is 1, 2 or 3, p is an integer of 1 to 3, q is an integer of 0 to 3, r is 0 or 1,
- M+ is a sulfonium cation having the formula (1A) or iodonium cation having the formula (1B):
- wherein R11 to R15 are each independently a C1-C20 monovalent hydrocarbon group which may contain a heteroatom, any two of R11, R12 and R13 may bond together to form a ring with the sulfur atom to which they are attached, and
- wherein the sulfonate anion in the onium salt is selected from the group consisting of the following formulae:
- wherein A1 is trifluoromethyl, and Me is methyl.
7 more elements
Dependencies are inferred from the claim text.