Photoactive compounds, photoresist compositions including the same, and pattern formation methods

A photoactive compound of formula (3a):

• wherein, ring CY1 is a C3-30 carbocyclic group or a C3-30 heterocyclic group, wherein the C3-30 heterocyclic group comprises a heteroatom selected from nitrogen, oxygen, or a combination thereof;
• each L1 independently is a single bond or a divalent linking group;
• each R8 independently is hydroxyl, —F, —I, —CF3, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl;
• a is an integer from 0 to 10;
• L2 is a single bond, —C(O)—, —C(O)O—, or —C(O)N(R5a)—, wherein R5a is hydrogen, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl;
• R9 is substituted C1-10 alkyl, substituted C3-20 cycloalkyl, substituted C3-20 heterocycloalkyl, substituted C6-10 aryl, or substituted C3-10 heteroaryl, and at least one substituent of the substituted R9 group is hydroxy, —I, or a combination thereof;
• and
• M+ is a sulfonium cation or an iodonium cation.

A photoresist composition, comprising:

• a photoactive compound;
• and
• a solvent,
• wherein photoactive compound is of formula (3a):
• wherein, ring CY1 is a C3-30 carbocyclic group or a C3-30heterocyclic group, wherein the C3-30 heterocyclic group comprises a heteroatom selected from nitrogen, oxygen, or a combination thereof;
• each L1 independently is a single bond or a divalent linking group;
• each R8 independently is hydroxyl, —F, —I, —CF3, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl;
• a is an integer from 0 to 10;
• L2 is a single bond, —C(O)—, —C(O)O—, or —C(O)N(R5a)—, wherein R5a is hydrogen, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl;
• R9 is substituted C1-10 alkyl, substituted C3-20 cycloalkyl, substituted C3-20 heterocycloalkyl, substituted C6-10 aryl, or substituted C3-10 heteroaryl, and at least one substituent of the substituted R9 group is hydroxy, —I, or a combination thereof;
• and
• M+ is a sulfonium cation or an iodonium cation.