| 摘要 |
PROBLEM TO BE SOLVED: To provide a wiring board in which a connecting part is rigidly connected to a wiring conductor of an external electric circuit board via a lead-free solder, and which can be rigidly mounted on the external circuit board with high reliability. SOLUTION: The wiring board includes an insulating base 1 having an electronic component placing part and a frame-like metal layer 4 surrounding the placing part on an upper surface and the connecting pad 4 on an outer periphery of a lower surface, and a groove-like recess 5a formed so as to connect the pad 4 and the layer 3 to a side face of the base 1 and covered on an inner wall surface with the conductor 6. A small-diameter part 5b having an inner diameter smaller than the other part is formed partly in the recess part 5a. The inner wall surface of the recess 5a covered with the conductor 5 is formed in an arcuate part having a radius of curvature of 5 to 50μm at a corner formed of the lower surface and the side face of the base 1. COPYRIGHT: (C)2004,JPO |
