| 摘要 |
PURPOSE:To obtain a multilayer substrate having low permittivity and practically enough strength by a method wherein one of insulating boards which form a multilayer board is a porous board of low permittivity the other is a fully sintered board of high permittivity, a conductor film is formed on the insulating board of high permittivity, and the insulating board of low permittivity is blocked by the porous insulating board of high permittivity. CONSTITUTION:A porous green sheet 9 of low permittivity is formed of material composed of SiO2 and a small amount of B2O3, a fully sintered-type green sheet 10 of high permittivity is formed of main material composed of B2O3 and alumina and sintered at a temperature of 900 deg.C, and conductor paste which contains metal components of copper or gold is printed on the substrate 10. The boards 9 and 10 are laminated and sintered at a temperature of 900 deg.C or so. The porous board 9 of low permittivity is set smaller in size than the board 10, and boards each surround with the fully sintered board 10 of high permittivity are alternately laminated and sintered into a laminated board 1 which is high in strength and low in permittivity. |
