| 摘要 |
PROBLEM TO BE SOLVED: To provide a fillet shape that can suppress the occurrence of red divisions and the liftoff and peeling of copper lands. SOLUTION: When projected solder is formed in the outermost block section of a copper land 2 in a reflow-soldering step and a printed board 4 on which the projected solder is formed is subjected to flow-soldering in a flow-soldering steps, a fillet having a projecting section in its outermost block section is formed. Since solder 1 used in the flow-soldering step is formed on the inside of the projecting section 12, no strong tensile stress is generated in the copper land 2 and the liftoff and peeling of the land 2 can be suppressed, at the same time, the occurrence of red divisions can also be suppressed by the projecting section 12.
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