Hitachi, Ltd.

Masaru Mitsumoto

Makoto Homma

Noriaki Mukai

Solder bumps are formed on a plurality of electrode parts of a printed substrate and a semiconductor chip is loaded on the printed substrate via the plurality of solder bumps. In this case, a thermoplastic film is prepared as an underfill that covers a surface of the printed substrate on which the solder bumps are formed. In the film, parts corresponding to the solder bumps are removed and a peripheral edge of a part on which the semiconductor chip will be loaded has a protruded form. After the printed substrate has been covered with the film, the film is bonded onto the board and the semiconductor chip is loaded on the printed substrate and carried into a reflow furnace. In the reflow furnace, heat and pressure are applied to fuse the solder bumps.

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Ryugasaki, Japan

Masaru Mitsumoto