No abstract

reduce the thermal shock resistance and mechanical strength of the glass composite. Preventing cristobalite formation A series of glass/ceramic composites were prepared may make this glass composite useful for forming low temf rom pyrex borosilicate glass with silica. T he eVects of perature, low dielectric glass+ceramic substrates. Several 15 vol.-% alumina addition on cristobalite formation in cristobalite growth inhibitors have been identi ed,11-13 one this system have been studied. Cristobalite formation of which is alumina. in the composites has been found to decrease with Alumina is conventionally used as a dielectric material addition of alumina, which may be attributed to a for microelectronic packaging because of its excellent strong coupling reaction between Al 3 + f rom alumina thermal, mechanical, and electrical (insulating) properties. and K+ f rom pyrex borosilicate glass. T he resultingAlumina based packaging, generally containing 4-10 wt-% glass/ceramic composites containing alumina have low glass, has a sintering temperature above 1500°C, which thermal expansion coeYcient owing to the presence of requires the use of refractory metals such as Mo or W for a lower amount of cristobalite in the glass matrix. T he the electrical interconnection, so that metal can be co red formation of cristobalite limits the eYciency of the with the ceramics.14 These metals have poor electrical ceramic substrate when used in circuit boards.conductivity compared with highly conductive metals such BCT /584as Ag, Ag-Pd, and Au, and require the use of strong reducing atmospheres during co ring.