A finely patterned silica type ceramic film suitable as an inter-layer dielectric
is formed in a short time by applying, onto a substrate, a positive working radiation
sensitive polysilazane composition comprising a modified poly(sil sesquiazane)
having a number average molecular weight of 100 to 100,000 and containing a basic
constituent unit represented by the general formula: [SiR6(NR7)1.5]
and other constituent units represented by the general formula: [SiR62NR7]
and/or [SiR63(NR7)0.5]
(R6 and R7 independently represent a hydrogen atom, a C1-3
alkyl group or a substituted or unsubstituted phenyl group) in a ratio of 0.1 to
100 mol-% to said basic constituent unit, a photo acid generator and preferably
a water-soluble compound as a shape stabilizer, then patternwise exposing the resultant
coating film, subjecting the exposed part of the coating film to moistening treatment,
developing it with an aqueous alkali solution, wholly exposing the coating film
to light and moistening treatment again, followed by burning treatment.
