| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve the problem that a wiring board cannot be strongly bonded with an external electric circuit board because of creeping-up of solder. SOLUTION: A wiring board 7 is provided with an insulated substrate 1 having an electronic component packaging part and a frame-like metal layer 3 surrounding the packaging part on the upper face, and having a connecting pad 4 on the outer peripheral part of the lower face; and a casteration conductor 5a for connecting the connecting pad 4 and the frame-like metal layer 3. The casteration conductor 5a is composed of a first area 5b and a second area 5c. The first area 5b and the second area 5c are deviated in positions in the width direction of the side face of the insulated substrate 1 and connected through an internal wiring layer 10 formed inside the insulated substrate 1 and at the corner formed of the lower face and side face of the insulated substrate 1. An area forming the first area of the casteration conductor is formed in the shape of circular arc having a curvature radius of 5 to 50μm.</p> |
