| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that a wiring board is not able to be joined firmly to an external electric circuit board due to the creep-up of solder. SOLUTION: The wiring board is provided with an insulating substrate 1 having an electronic component mounting section and a frame-like metal layer 3 surrounding the mounting section on its upper surface and connection pads 4 in the outer peripheral section of its lower surface and groove-like recesses 5a which are formed on side faces of the substrate 1 so as to connect the pads 4 to the metal layer 3 and carry conductors 6 adhered to the internal wall surfaces. At part of each recess 5a, a small-diameter section 5b having a smaller inside diameter than the other portion of the section 5a has is formed and areas of the connection pads 4 formed at long-distance positions from the center of the lower surface of the insulating substrate 1 are made larger than those of connection pads 4 formed at short-distance positions from the center. COPYRIGHT: (C)2004,JPO |
