Resin composition, resin sheet, multilayer printed wiring board, and semiconductor device

A resin composition comprising:

• a maleimide compound (A) comprising a constituent unit represented by the following formula (1), and maleimide groups at both ends of the molecular chain;
• a photo initiator (B1) represented by the following formula (2) and/or a photo initiator (B2) represented by the following formula (3);
• and
• a photo initiator (C) represented by the following formula (4):
• wherein R1 represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms;
• R2 represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms;
• each R3 independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 16 carbon atoms, or a linear or branched alkenyl group having 2 to 16 carbon atoms;
• and each n1 independently represents an integer of 1 to 10,
• wherein R4 represents an acetyl group or a benzoyl group;
• R5 represents a phenyl group or naphthyl group optionally having a substituent;
• R6 represents a hydrogen atom, or a linear or branched alkyl group having 1 to 16 carbon atoms and optionally having a substituent;
• each R7 independently represents a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms and optionally having a substituent;
• and each n2 independently represents an integer of 1 to 5,
• wherein R8 represents an aryl group having 6 to 24 carbon atoms and optionally having a substituent, or a heteroaryl group having 3 to 24 carbon atoms and optionally having a substituent;
• R9 represents an acetyl group or a benzoyl group;
• R10 represents a hydrogen atom, or a linear or branched alkyl group having 1 to 16 carbon atoms and optionally having a substituent;
• and X represents an oxygen atom or a sulfur atom,
• wherein each R11 independently represents a group represented by the following formula (5) or a phenyl group:
• wherein —* represents a bonding site, and each R12 independently represents a hydrogen atom or a methyl group.