PRINTED CIRCUIT BOARD AND METHOD FOR SOLDERING TO ITS THROUGH HOLE

摘要

PROBLEM TO BE SOLVED: To contribute to prevention of a lead contamination of a global environment by enabling a sufficient rising of even a lead-free solder having poor wettability to a through hole and enabling filling of the solder of a sufficient amount to an upper part of the hole and enabling lead-free solder mounting. SOLUTION: A method for soldering to the through hole of a printed circuit board comprises the steps of forming the hole 12 so that a bore is enlarged in a tapered state toward a front surface 13a or a rear surface 13b of a laminate 13, and sufficiently filling the lead-free solder 4 to the upper part of the hole by sufficiently raising the solder 4 to the hole in the case of automatically soldering.