| US 7,575,850 B2 | ||
| Chemically amplified resist composition | ||
| Yoshiyuki Takata, Toyonaka (Japan); Satoshi Yamamoto, Hyogo (Japan); and Satoshi Yamaguchi, Kawachinagano (Japan) | ||
| Assigned to Sumitomo Chemical Company, Limited, Tokyo (Japan) | ||
| Filed on Jan. 28, 2008, as Appl. No. 12/21,149. | ||
| Claims priority of application No. 2007-018998 (JP), filed on Jan. 30, 2007. | ||
| Prior Publication US 2008/0193874 A1, Aug. 14, 2008 | ||
| Int. Cl. G03F 7/004 (2006.01) | ||
| U.S. Cl. 430—270.1 [430/910; 430/921; 430/922] | 14 Claims |
| 1. A chemically amplified resist composition comprising:
a resin which comprises a structural unit having an acid-labile group and a structural unit represented by the formula (I):
 wherein R1 represents a hydrogen atom or a methyl group, ring X represents a C3-C30 cyclic hydrocarbon group in which one —CH2— is substituted with —COO—, and at least one hydrogen atom in the C3-C30 cyclic hydrocarbon group may be substituted, and
p represents an integer of 1 to 4, and which itself is insoluble or poorly soluble in an alkali aqueous solution but becomes
soluble in an alkali aqueous solution by the action of an acid, and
at least two salts selected from a salt represented by the formula (II):
 wherein Y1 and Y2 each independently represent a fluorine atom or a C1-C6 perfluoroalkyl group, A+ represents an organic counter ion and R21 represents a C1-C30 hydrocarbon group which may be substituted and at least one —CH2— in the C1-C30 hydrocarbon group may be substituted with —CO— or —O—, and a salt represented by the formula (III):
A′+−O3S—R23 (III)
wherein R23 represents a C1-C8 linear or branched chain perfluoroalkyl group and A′+ represents an organic counter ion.
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