Connection substrate

A connection substrate comprising a ceramic substrate comprising a through hole therein and a through conductor formed in said through hole and having a first main surface and a second main surface:

• said through conductor comprising;
• a metal porous body comprising a metal matrix and pores, said pores comprising first open pores communicating with said first main surface and second open pores communicating with said second main surface;
• first glass phases provided in said first open pores, respectively;
• second glass phases formed in said second open pores, respectively;
• first spaces provided in said first open pores, respectively;
• and
• second spaces provided in said second open pores, respectively,
• wherein said first spaces comprise closed spaces which do not communicate with said first main surface, and
• wherein said second spaces comprise open spaces communicating with said second main surface.