Patent ID: 10278286

Abstract:
A through conductor 11 provided in a through hole of a ceramic substrate includes a metal porous body 20, glass phases 17 and 19 formed in pores 16A to 16D of the metal porous body 20 and spaces 30 and 31 in the pores. A ratio of an area of the pores is 5 to 50 percent in a cross section of the through conductor 11. It is provided that the through conductor 11 is separated into a first part 11A on a side of the first main surface 11a and a second part 11B on a side of the second main surface 11b in a direction B of thickness of the ceramic substrate, a ratio of an area of glass phases occupying the pores in the first part 11A is higher than a ratio of an area of glass phases occupying the pores in the second part 11B. A ratio of an area of spaces occupying the pores in the first part 11A is lower than a ratio of an area of the pores occupying the pores in the second part 11B.