Wiring board and method for manufacturing the same

A method for manufacturing a wiring board, comprising:

• forming a first penetrating hole in a substrate such that the first through-hole penetrates through the substrate between a first surface of the substrate and a second surface of the substrate on an opposite side of the first surface;
• forming a first through-hole conductor on an inner wall of the first penetrating hole;
• forming a first conductive circuit on the first surface of the substrate;
• forming a second conductive circuit on the second surface of the substrate such that the second conductive circuit is connected to the first conductive circuit by the first through-hole conductor;
• filling a filler in the first through-hole conductor;
• forming a second penetrating hole in the filler;
• forming a second through-hole conductor in the second penetrating hole;
• forming a first conductive portion on one end of the second penetrating hole;
• and
• forming a second conductive portion on an opposite end of the second penetrating hole such that the second conductive portion is connected to the first conductive portion by the second through-hole conductor,
• wherein the first and second conductive circuits have thicknesses which are formed to be thicker than thicknesses of the first and second conductive portions.