| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that a wiring board cannot be joined firmly to an external electric circuit board due to the creeping-up of a solder. SOLUTION: The wiring board has an insulating base 1 in which an electronic component mounting portion and a frame-like metal layer 3 for surrounding the mounting portion are provided on an upper surface, a connection pad 4 is provided at the outer periphery of a lower surface, and a grooved recess 5a formed to connect the connecting pad 4 to the frame-like metal layer 3 to the side face of the insulating base 1 and covered with conductor 6 on the surface of an inner wall. A small-diameter portion 5b smaller in an inner diameter than the other portion is formed on the part of the grooved recess 5a. A protruding portion 4a or the recessed portion is formed on the surface of the connecting pard 4. COPYRIGHT: (C)2004,JPO |
