Abstract: A dielectric material is disclosed which has a small absolute value of the temperature coefficient of resonance frequency and a high coefficient of unloaded quality. Also disclosed are a process for producing the dielectric material and multilayer and other circuit boards containing the dielectric material. The dielectric material is a highly densified material having a water absorption lower than 0.1%, which is obtained by mixing 95.5 to 99.5 percent by weight mixture of a glass frit and a strontium compound with 0.5 to 4.5 percent by weight titanium dioxide, compacting the resultant mixture, and sintering the compact at a relatively low temperature around 930.degree. C. This dielectric material is a glass ceramic containing strontium anorthite (SrAl.sub.2 Si.sub.2 O.sub.8) as the main crystalline phase, and may contain the TiO.sub.2, which remains unchanged after sintering. The absolute value of the temperature coefficient of resonance frequency of the dielectric material is 20 ppm/.degree. C.

Abstract: Powders of BaCO.sub.3, TiO.sub.2, ZnO, etc. are mixed to each other at a predetermined ratio of quantity, calcined in an atmospheric air at 90.degree.-120.degree. C., and pulverized to obtain a calcined powder having an average grain size from 1 to 3 .mu. m. 0.1 to 20 parts-by weight of a powder having an average grain size from 0.1 to 1.5 .mu.m comprising a glass having a transition point of not higher than 450.degree. C. obtained by mixing powders of Pb.sub.3 O.sub.4, SiO.sub.2, Na.sub.2 O, etc. to each other, melting and then pouring into water and pulverizing the thus obtained glass is admixed to the calcined powder. The mixture is dried, pelleted by adding a resin and the pellet powder is molded into a cylindrical shape, applied with CIP (Cold isotactic press), and the molding product after the treatment is sintered in an atmospheric air at 850.degree. to 1000.degree. C. to obtain a dielectric ceramic sintered at low temperature.

Abstract: The invention provides a glass-ceramic composite with sufficient strength and other excellent properties suitable for IC packages or multilayer substrates. The glass-ceramic composite of the invention includes crystallized glass and at least either of alumina and mullite at the ratio by weight of eighty through fifty-five to twenty through forty-five. The crystallized glass includes cordierite as primary crystals and contains 40 to 52 percent by weight of silicon dioxide or SiO.sub.2, 27 to 37 percent by weight of aluminum oxide or Al.sub.2 O.sub.3, 11 to 13 percent by weight of magnesium oxide or MgO, 2 to 8 percent by weight of diboron trioxides or B.sub.2 O.sub.3, 2 to 8 percent by weight of calcium oxide or CaO, and 0.1 to 3 percent by weight of zirconium oxide or ZrO.sub.2.

Abstract: A ceramic substrate is described consisting essentially of a crystallized glass and having at least one throught-hole filled with a conductor material having 100 parts by weight of copper and form 1 to 30 parts by weight of a glass having a softening point of 1,000.degree. C. or less and a thermal expansion coefficient of from 1.5.times.10.sup.-6 /K to 4.0.times.10.sup.-6 /K as measured in a temperature range of from room temperature to 400.degree. C.

Abstract: The invention provides a glass-ceramic composite with sufficient strength and other excellent properties suitable for IC packages or multilayer substrates. The glass-ceramic composite of the invention includes crystallized glass and at least either of alumina and mullite at the ratio by weight of eighty through fifty-five to twenty through forty-five. The crystallized glass includes cordierite as primary crystals and contains 40 to 52 percent by weight of silicon dioxide or SiO.sub.2, 27 to 37 percent by weight of aluminum oxide or Al.sub.2 O.sub.3, 11 to 13 percent by weight of magnesium oxide or MgO, 2 to 8 percent by weight of diboron trioxides or B.sub.2 O.sub.3, 2 to 8 percent by weight of calcium oxide or CaO, and 0.1 to 3 percent by weight of zirconium oxide or ZrO.sub.2.