R. Hsu et al., MODIFIED OXIDE SOL-GEL (MOSG) SYNTHESIS OF BOROPHOSPHOSILICATE GLASSES AND GLASS-CERAMICS, Journal of Materials Science, 30(12), 1995, pp. 3123-3129
A modified oxide sol-gel (MOSG) process was used to synthesize boropho
sphosilicate glasses and glass-ceramics using boron oxide and phosphor
ous pentoxide as starting precursors. The oxide precursors were used t
o form alkoxides in situ, which were then hydrolysed and condensed to
form borophosphosilicate gels. The dried gels were analysed for their
thermal properties and were heat treated accordingly, at a temperature
of 800 degrees C, to crystallize the boron phosphate phase. The resul
tant xerogels were then analysed for their microstructure. Both pressu
reless and hot-pressing techniques were used to sinter the calcined ge
ls to form glass-ceramics. The sintered samples were characterized for
their microstructure using electron microscopy and evaluated for thei
r dielectric properties. Dielectric measurements indicate that the sin
tered glass-ceramics possess dielectric constants less than 5 and diss
ipation factors less than 0.001 at a frequency of 1 MHz. The results o
f these studies show the potential of the oxide sol-gel-derived boroph
osphosilicate glass-ceramics for use as substrate materials in microel
ectronic packaging.