| abstract |
The present invention relates to a photocurable thermosetting resin composition capable of forming a cured film having PCT resistance, HAST resistance, electroless gold plating resistance, and cold shock resistance, which are important as solder resists for semiconductor packages, dry films and cured products thereof, and solders thereof. Provided is a printed wiring board on which a cured film such as a resist is formed. The photocurable thermosetting resin composition which can be developed by aqueous alkali solution contains a carboxyl group-containing resin, a photoinitiator, a vinyl group-containing elastomer, and a mercapto compound. It is preferable that the said carboxyl group-containing resin is not derived from an epoxy resin. |