| 摘要 |
PROBLEM TO BE SOLVED: To provide a wiring board which is enhanced in connection reliability by a method wherein a force induced by a thermal expansion coefficient difference between the wiring board and a mounted part and applied to a joint between them is lessened. SOLUTION: A wiring board 10 is equipped with a resin layer 14 and wiring layers 18 and 20 formed on both the surfaces of the resin layer 14. No wiring layer is formed on the rear surface of the board 10 corresponding to its front region where an IC chip 30 is mounted. The resin layer 14 is formed thinner in a region where the IC chip chip 30 is mounted than in the other region. As no wiring layer is formed on the rear region of the board opposed to its front region where a mounting part is mounted, a distortion of the wiring board 10 caused by a thermal expansion difference between the resin layer and the wiring layer attendant on a temperature change after a mounted part is mounted is prevented from occurring in a part mounting region. Therefore, a force that is induced by the distortion caused by a temperature change and applied to a joint of a mounting part is lessened, so that a mounting part can be improved in joint reliability.
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