| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method of a novolac type phenol resin that enables production of a photoresist composition having high heat resistance, high sensitivity, a high film residual rate and high resolution, a novolac type phenol resin, and a photoresist composition.SOLUTION: The production method includes: a first step of reacting naphthols (a1), cresols (b1) and formaldehydes (c1) to obtain an intermediate reaction product containing a trinuclear compound represented by formula 1 by 10 to 80 mass%; a second step of removing unreacted naphthols until the content of unreacted naphthols (a1) in the intermediate reaction product obtained in the first step is decreased to 10 mass% or less; and a third step of reacting the intermediate reaction product processed in the second step with cresols (b2) and formaldehydes (c2) to obtain a novolac type phenol resin. |
