Bump formation method

摘要

A method for forming bumps in an LSI package in which: semiconductor chips are mounted onto a flexible printed circuit board; electrically conductive balls are temporarily fixed by using a fixing liquid including one selected from a group including flux, solder paste and an adhesive containing an electrically conductive agent, onto pads which are provided on the flexible printed circuit board so as to be electrically connected to the semiconductor chips; the flexible printed circuit board having the electrically conductive balls temporarily fixed thereto is wound up onto a reel; the flexible printed circuit board having the electrically conductive balls temporarily fixed thereto is fed out from the reel and heated to thereby form bumps thereon; and the flexible printed circuit board having the bumps formed thereon is wound up onto another reel; and the flexible printed circuit board is cleansed and trimmed to thereby form LSI packages.