A manufacturing method of a chip-attached substrate includes preparing a stacked substrate including multiple chips, a first substrate to which the multiple chips are temporarily bonded, and a second substrate bonded to the first substrate with the multiple chips therebetween; and separating the multiple chips bonded to the first substrate and the second substrate from the first substrate to bond the multiple chips to one surface of a third substrate including a device layer.

A release agent composition for light irradiation release or an adhesive composition for light irradiation release, contains a Novolac resin having at least one of a hydroxy group directly bonded to an aromatic ring and a carboxy group directly bonded to an aromatic ring, and a siloxane backbone-containing epoxy resin, and a solvent.