MODIFIED OXIDE SOL-GEL (MOSG) SYNTHESIS OF BOROPHOSPHOSILICATE GLASSES AND GLASS-CERAMICS

A modified oxide sol-gel (MOSG) process was used to synthesize borophosphosilicate glasses and glass-ceramics using boron oxide and phosphorous pentoxide as starting precursors. The oxide precursors were used to 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 resultant xerogels were then analysed for their microstructure. Both pressureless and hot-pressing techniques were used to sinter the calcined gels to form glass-ceramics. The sintered samples were characterized for their microstructure using electron microscopy and evaluated for their dielectric properties. Dielectric measurements indicate that the sintered glass-ceramics possess dielectric constants less than 5 and dissipation factors less than 0.001 at a frequency of 1 MHz. The results of these studies show the potential of the oxide sol-gel-derived borophosphosilicate glass-ceramics for use as substrate materials in microelectronic packaging.