| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a wiring board with its through holes thoroughly filled with metal plating for through-hole conductor formation and has high connection reliability. <P>SOLUTION: The wiring board 5 comprises a first wiring conductor layer 2 made of a metal foil and arranged on the lower surface of an insulating layer 1, a second wiring conductor layer 3 made of a metal foil and arranged on the upper surface of the insulating layer 1, and a through-hole conductor 4 composed of a plated metal filling a through hole 9 formed in the insulating layer 1 on the first wiring conductor layer 2 for electrically connecting the first wiring conductor layer 2 and the second wiring conductor 3. It is so set that H≤L≤H+T, wherein L is the distance from the upper end of the outer circumference of the through hole 9 to the end of the inner circumference of the second wiring conductor layer 3 which surrounds the upper end of the outer circumference of the through hole 9, H is the depth of the through hole 9, and T is the thickness of the second wiring conductor layer 3. The arithmetic average roughness Ra of the inner circumferential surface of the through hole 9 falls in a range of 0.3-0.6μm. <P>COPYRIGHT: (C)2004,JPO</p> |
