| 摘要 |
PROBLEM TO BE SOLVED: To provide a printed circuit board where lead-free soldering is sufficiently leaked and spread to an upper land electrode, and lift-off or land peeling is prevented from being generated in a flow method using the lead-free soldering. SOLUTION: Three or more mini Bayers 14 are formed at the outer peripheral part of an upper land electrode 12a. The heating and cooling of the outer peripheral part of the upper land electrode 12a is promoted by the heat transferring effects of the mini Bayers 14, and the wettability of solder is improved, and the generation of lift-off is prevented. Also, the generation of land peeling is prevented by the reinforcing effects of the mini Bayers 14. In this case, the mini Bayers may be arranged outside the land electrode 12a, and the mini Bayers may be connected through a metallic layer to the land electrode. COPYRIGHT: (C)2004,JPO&NCIPI
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