| 摘要 |
PROBLEM TO BE SOLVED: To provide a ceramic substrate capable of suppressing the degradation of performance of the ceramic substrate due to the infiltration of a plating liquid and water from a surface. SOLUTION: The ceramic substrate has a laminate formed by laminating first and second insulating layers made of glass ceramic containing B<SB>2</SB>C<SB>3</SB>, an alkaline metal oxide, and an alkaline-earth metal oxide, the second insulating layer being positioned as a top layer. The second insulating layer is laminated on the first insulating layer, wherein the first insulating layer has 30 mass% or less of total amount of the B<SB>2</SB>C<SB>3</SB>, alkaline metal oxide and alkaline-earth metal oxide with respect to the whole inorganic components, and the second insulating layer has 40 mass% or more of total amount of the B<SB>2</SB>C<SB>3</SB>, alkaline metal oxide and alkaline-earth metal oxide with respect to the whole inorganic components. The first and second insulating layers respectively have through-holes in which conductors are provided and which communicate with each other, an opening edge of a first through-hole of the first insulating layer on the side of the second insulating layer being inside an opening edge of a second through-hole of the second insulating layer on the side of the first insulating layer. COPYRIGHT: (C)2010,JPO&INPIT |
