A photocurable and thermosetting resin composition comprises (A) a high
purity synthetic silica powder having a uranium content of not more than
1.0 ppb, (B) a photosensitive prepolymer containing a carboxylic group and
at least two ethylenically unsaturated groups in its molecule and having
an acid value of solid content of 50 to 150 mg KOH/g, (C) a photosensitive
(meth)acrylate compound, (D) a photopolymerization initiator, (E) an epoxy
resin, and (F) a curing catalyst. A cured film which emits alpha rays at a
fully low dose is obtained by forming a film of the composition on a
substrate, subjecting the film to exposure to light and development, and
finally curing the coating film by irradiation with active energy rays
and/or thermal curing.
