Resist composition and patterning process

A resist composition comprising a base polymer, a crosslinker and a quencher containing an iodonium salt having the formula (A):

• wherein R1 is a nitro group, hydroxyl group or a group having the formula (A-1) below, R2 is fluorine or trifluoromethyl, R3 is methyl or cyano, R4 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, R5 is an optionally substituted phenyl group having the formula (A-2) below or an optionally substituted ethynyl group having the formula (A-3) below, m is an integer of 1 to 4, n is an integer of 0 to 3, and p is an integer of 0 to 5,
• wherein R6 and R7 are each independently hydrogen or a straight, branched or cyclic C1-C6 alkyl group, R6 and R7 may bond together to form a ring with the nitrogen atom to which they are attached, which ring may contain an ether bond,
• R8 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group,
• R9 is hydrogen, hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, and q is an integer of 0 to 5, and
• wherein the base polymer is free of an acid labile group.

A resist composition comprising a base polymer and a quencher containing an iodonium salt having the formula (A):

• wherein R1 is a nitro group, hydroxyl group or a group having the formula (A-1) below, R2 is fluorine or trifluoromethyl, R3 is methyl or cyano, R4 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, R5 is an optionally substituted phenyl group having the formula (A-2) below or an optionally substituted ethynyl group having the formula (A-3) below, m is an integer of 1 to 4, n is an integer of 0 to 3, and p is an integer of 0 to 5,
• wherein R6 and R7 are each independently hydrogen or a straight, branched or cyclic C1-C6 alkyl group, R6 and R7 may bond together to form a ring with the nitrogen atom to which they are attached, which ring may contain an ether bond,
• R8 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group,
• R9 is hydrogen, hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, and q is an integer of 0 to 5,
• wherein the base polymer is free of an acid labile group, and
• wherein the resist composition is a chemically amplified negative resist composition.

A resist composition comprising a base polymer and a quencher containing an iodonium salt having the formula (A):

• wherein R1 is a nitro group, hydroxyl group or a group having the formula (A-1) below, R2 is fluorine or trifluoromethyl, R3 is methyl or cyano, R4 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, R5 is an optionally substituted phenyl group having the formula (A-2) below or an optionally substituted ethynyl group having the formula (A-3) below, m is an integer of 1 to 4, n is an integer of 0 to 3, and p is an integer of 0 to 5,
• wherein R6 and R7 are each independently hydrogen or a straight, branched or cyclic C1-C6 alkyl group, R6 and R7 may bond together to form a ring with the nitrogen atom to which they are attached, which ring may contain an ether bond,
• R8 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group,
• R9 is hydrogen, hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, and q is an integer of 0 to 5,
• wherein the base polymer further comprises recurring units of at least one type selected from the formulae (f1) to (f3):
• wherein RA is each independently hydrogen or methyl,
• Z1 is a single bond, phenylene group, —O—Z11— or —C(═O)—Z12—Z11—, Z11 is (1) a straight, branched or cyclic C1-C6 alkylene which may contain a carbonyl, ester, ether or hydroxy moiety, (2) a straight, branched or cyclic C2-C6 alkenylene group which may contain a carbonyl, ester, ether or hydroxy moiety, or (3) a phenylene group, Z12 is —O— or —NH—,
• R21, R22, R23, R24, R25, R26, R27 and R28 are each independently a straight, branched or cyclic C1-C12 alkyl group which may contain a carbonyl, ester or ether moiety, or C6-C12 aryl group or C7-C20 aralkyl group, in R21, R22, R23, R24, R25, R26, R27 and R28 at least one hydrogen may be substituted by a C1-C10 straight, branched or cyclic alkyl moiety, halogen, trifluoromethyl, cyano, nitro, hydroxyl, mercapto, C1-C10 straight, branched or cyclic alkoxy moiety, C2-C10 straight, branched or cyclic alkoxycarbonyl moiety, or C2-C10 straight, branched or cyclic acyloxy moiety, R23 and R24, or R26 and R27 may bond together directly or via a methylene moiety or ether bond to form a ring with the sulfur atom to which they are attached,
• Z2 is a single bond, —Z21—C(═O)—O—, —Z21—O— or —Z21—O—C(═O)—, Z21 is a straight, branched or cyclic C1-C12 alkylene group which may contain a carbonyl, ester or ether moiety,
• Z3 is a single bond, methylene group, ethylene group, phenylene group, fluorinated phenylene group, —O—Z31—, or —C(═O)—Z32-Z31—, Z31 is (1) a straight, branched or cyclic C1-C6 alkylene group which may contain a carbonyl, ester, ether, fluorine or hydroxyl moiety, (2) a straight, branched or cyclic C2-C6 alkenylene group which may contain a carbonyl, ester, ether, fluorine or hydroxyl moiety, (3) a phenylene group, (4) a fluorinated phenylene group or (5) a trifluoromethyl-substituted phenylene group, Z32 is —O— or —NH—,
• A1 is hydrogen or trifluoromethyl, and
• M− is a non-nucleophilic counter ion.

A process for forming a pattern comprising the steps of applying a resist composition onto a substrate, baking to form a resist film, exposing the resist film to high-energy radiation, and developing the exposed film in a developer,

• wherein the high-energy radiation is electron beam or extreme ultraviolet radiation of wavelength 3 to 15 nm, and
• wherein the resist composition comprises a base polymer and a quencher containing an iodonium salt having the formula (A):
• wherein R1 is a nitro group, hydroxyl group or a group having the formula (A-1) below, R2 is fluorine or trifluoromethyl, R3 is methyl or cyano, R4 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, R5 is an optionally substituted phenyl group having the formula (A-2) below or an optionally substituted ethynyl group having the formula (A-3) below, m is an integer of 1 to 4, n is an integer of 0 to 3, and p is an integer of 0 to 5,
• wherein R6 and R7 are each independently hydrogen or a straight, branched or cyclic C1-C6 alkyl group, R6 and R7 may bond together to form a ring with the nitrogen atom to which they are attached, which ring may contain an ether bond,
• R8 is hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group,
• R9 is hydrogen, hydroxyl, halogen, trifluoromethyl, nitro, carboxyl, a C2-C10 acyl group, C2-C10 acyloxy group, C2-C10 alkoxycarbonyl group, a straight, branched or cyclic C1-C12 alkyl group which may contain oxo, a straight, branched or cyclic C2-C12 alkenyl group which may contain oxo, a straight, branched or cyclic C1-C12 alkoxy group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxyalkyl group, and q is an integer of 0 to 5.