Non-ionic photoacid generators, photoresist compositions, and pattern formation methods

A non-ionic photoacid generator compound represented by Formula (1) or (2):

• wherein, in Formula (1) and (2),
• ring A1 is a monocyclic C3-60 aromatic group, a polycyclic C3-60 aromatic group, a C3-15 monoalicyclic group, or a C3-15 polyalicyclic group,
• each L1 is independently a single bond or one or more linking groups, wherein L1 is free of fluorine,
• each L2 is independently a single bond or one or more divalent linking groups,
• P is a polymerizable group,
• each R1a, R1b, R1c, and R1d is independently a non-hydrogen substituent, wherein each of R1a, R1b, R1c, and R1d optionally further comprises one or more divalent linking groups as part of its structure, and wherein R1a and R1b are optionally linked together to form an aromatic or non-aromatic ring group, and R1c and R1d are optionally linked together to form an aromatic or non-aromatic ring group,
• each R2 is independently a monovalent non-hydrogen substituent;
• wherein each R2 optionally further comprises one or more divalent linking groups as part of its structure,
• each X1 is independently —O—, —S—, —N(R2a)—, —C(O)—, —S(O)R2a—, or —S(O2)R2a—, wherein R2a is independently chosen from substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C1-20 heteroalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl,
• each Z1 independently comprises an anion stabilizing group, wherein at least one Z1 is configured to form an intramolecular non-covalent bond with an anion derived from the sulfonate group to form a ring having from 5 to 8 ring atoms, wherein Z1 is independently chosen from —OH, —C(O)OH, —SH, —C(O)SH, —NHS(O)2R3, —S(O)2R3, —S(O)R3, —S(O)2NHS(O)2R3, —CH(═NOH), or —B(R4)2;
• wherein each Z1 optionally further comprises one or more divalent linking groups as part of its structure,
• each R3 is independently chosen from trifluoromethyl, hydroxyl, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C1-20 heteroalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl,
• each R4 is independently chosen from hydrogen, fluorine, hydroxyl, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C1-20 heteroalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl,
• two R2 together optionally form a fused ring with ring A1, wherein the fused ring optionally further comprises one or more divalent linking groups as part of its structure,
• one Z1 and one R2 together optionally form a fused ring with ring A1, wherein the fused ring optionally further comprises one or more divalent linking groups as part of its structure,
• each a and b is independently an integer from 0 to 2, provided that a sum of a and b is 1 or greater,
• c is an integer from 0 to 10,
• d is an integer from 1 to 3,
• e is 0 or 1, and
• n is an integer from 0 to 4.