Sintered glass-ceramic bodies having low dielectric constant - contg. polycrystalline, refractory, ceramic phase and glass phase

摘要

Sintered glass-ceramic bodies having a low dielectric constant contain a poly-crystalline, refractory, ceramic phase and a glass phase (borosilicate or alumina-borosilicate) formed between the crystalline aggregates in an amt. of 25-65 wt % (pref. 35-50 wt %) w.r.t. the whole material. The ceramic phase is pref. alumina, spodumene, wollastonite, magnesium silicate and/or kyanite; it can be acidic, basic or neutral. The material is used for electric insulation, esp. for multilayer electronic packages. The dielectric constant is low (the ceramic phase 6-9; the glass phase 5.0; the dielectric constant of the material as a whole is 4.3-6.2) and so is the coefft. of thermal expansion (5 x 10-6 degrees C-1, esp. 3.3-4.5 x 10-6 degrees C-1). The sintering temp. is relatively low (825-929 degrees C); therefore, the material can be metallised with Ag, Cu or an, or their alloys with Pd or Pt. The material has high density (2.15-2.35 g/cm3) and is impermeable to liquids and gases. The bending strength is high (2100-4200 kg/cm2). The dielectric loss is low (0.05, pref. 0.001 at 1 kH2-200 MH2). The thermal conductivity is high.