摘要 |
PROBLEM TO BE SOLVED: To provide a circuit board of GBA structure in which the high-density mounting of semiconductor elements is possible and which can be manufactured at low cost. SOLUTION: This circuit board contains, as mandatory conditions, a unit structure A2 consisting of an insulating base material 1, a conductive thin layer (conductor circuit) 2, which is made on one side 1a of the insulating base material 1, a hole 9, which is made, boring, in thickness direction, the insulating base material from the other side 1b of the insulating base material 1 to the interface 2a with the conductive thin layer 2 or to its vicinity, and a conductive material 10 which is charged at least in the base part 9a out of the hole. And, a projection 10c is made by protruding the conductive material 10 from the other side 1b of the insulating base material, and the projection 10c is made to function as a bump electrode. |