| 摘要 |
PROBLEM TO BE SOLVED: To provide a wiring board excellent in electrical reliability and heat dissipation property.SOLUTION: A wiring board 1 comprises an insulating substrate 11, a through hole 12 which pierces the insulating substrate 11 in a thickness direction and a filling conductor 15 provided in the through hole 12. The through hole 12 has a first region 13 which is located at a central part of the insulating substrate 11 in the thickness direction and has a first inner wall 13a, and a second region 14 which is a region from an end of the first region 13 to an end of the through hole 12 and has a second inner wall 14a which has a diameter increasing with the increasing distance from the end of the first region 13 toward the end of the through hole 12 and which is tilted to the first inner wall 13a. A corner between the first inner wall 13a and the second inner wall 14a is rounded. |
