Method for manufacturing liquid ejection head, and liquid ejection head

A method for manufacturing a liquid ejection head in which an ejection orifice-forming member that forms ejection orifices for ejecting a liquid and a flow path for the liquid that communicates with the ejection orifices is formed on a substrate, the manufacturing method comprising:

• forming a mold for the flow path for the liquid on the substrate;
• coating a photosensitive resin composition for forming the ejection orifice-forming member onto the substrate, on which the mold has been formed, to form a cationically polymerizable resin layer;
• and
• exposing and developing the cationically polymerizable resin layer to form the ejection orifice-forming member, wherein
• the photosensitive resin composition comprises at least one epoxy resin selected from the group consisting of an alicyclic epoxy resin and a glycidyl epoxy resin, and a cationic photopolymerization initiator (A),
• the cationic photopolymerization initiator (A) is a salt having an anion represented by a following formula (1), and
• a molar absorption coefficient of the cationic photopolymerization initiator (A) at a wavelength of 365 nm is at least 0.1 L/mol·cm:
• in formula (1), R1 to R4 are each independently an alkyl group having 1 to 18 carbon atoms or Ar, provided that at least one of the R1 to R4 is Ar,
• the Ar is an aryl group having 6 to 14 carbon atoms (not including the number of carbon atoms in following substituents), and some of hydrogen atoms in the aryl group may be substituted with an alkyl group having 1 to 18 carbon atoms, an alkyl group having 1 to 8 carbon atoms substituted with a halogen atom, an alkenyl group having 2 to 18 carbon atoms, an alkynyl group having 2 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, a nitro group, a hydroxyl group, a cyano group, an alkoxy group or aryloxy group represented by —OR6, an acyl group represented by R7CO—, an acyloxy group represented by R8COO—, an alkylthio group or arylthio group represented by —SR9, an amino group represented by —NR10R11, or a halogen atom, the R6 to R9 are each independently an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 14 carbon atoms, and the R10 and R11 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms.