| 摘要 |
PROBLEM TO BE SOLVED: To improve bonding reliability to impacts, such as impact of falling and both warp and bending, in bonding wherein an electrode of a surface mount ing component is bonded on a land of a surface part through soldering. SOLUTION: A land 22 of a printed board 11 is formed into an elliptical shape having sufficiently large area to a solder bonding surface 22a, to which a solder ball 13 is bonded. An aperture part 23a arranged on a resist film 23 is formed into a circular shape, where rightward eccentricity is made to the land 22 and a part of the aperture part 23a is protruded from the land 22. As a result, a part of an outer peripheral edge of the land 22 is made an over- resist structure covered with the resist film 23, and the rest is made a nonover- resist structure, where a fine gap S is formed to the resist film 23.
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