| 摘要 |
PROBLEM TO BE SOLVED: To provide a solder paste which has good wetting spreadability and which is stable with the lapse of time by solving such problems that the fillet formed between a lead and a land can not possess a sufficiently wide range and the joining strength is weak when parts are mounted and the reflow is executed on the land because the solder paste does not spread on the whole land in the case of coating a small amount of conventional solder paste on the land of a printed board, and further a conventional solder paste having good wetting spreadability shows variation with time during long term use and is inconvenient to use. SOLUTION: This solder paste has 0.1-7 wt.% 5-chlorobenzotriazole added in the flux in the solder paste, or has 0.7-7 wt.% derivative with a phenyl group introduced into the skelton of 5-chlorobenzotriazole added in the flux of the solder paste.
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