Modified Oxide Sol-Precipitation (MOSP) Approach for Synthesizing Borophosphosilicate Glasses and Glass−Ceramics

A modified oxide sol-precipitation process (MOSP) was used to synthesize borophosphosilicate glasses and glass−ceramics utilizing boron oxide and phosphorous pentoxide precursors. The oxide precursors were used to form alkoxides in situ, which were then partially hydrolyzed. Excess ammonium hydroxide was added to initiate a precipitation reaction. The resultant precipitate was centrifuged and separated from the supernatant liquid. The thermal properties of the dried precipitates were analyzed and the precipitates were accordingly heat treated to 800 °C, in order to crystallize the boron phosphate phase. Pressureless sintering was used to sinter the powders and form glass−ceramics. Microstructures of the sintered samples were then characterized using electron microscopy, and the dielectric properties were measured. Dielectric measurements indicate that the sintered glass−ceramics possess dielectric constants less than 4.0 and dissipation factors less than 0.001 at a frequency of 1 MHz. Results of these studies show that the modified oxide sol-precipitation is a viable approach for synthesizing borophosphosilicate glass−ceramics for use as substrate materials in microelectronic packaging.