Fujitsu Corporation

Nobuo Igusa

Keiji Watanabe

Ei Yano

Yasuo Yamagishi

Masayuki Ochiai

Isamu Takachi

Katsuhiro Inoue

Takeshi Ohori

The defluxing agent for flux residue after soldering contains an acid (preferably an organic acid, and particularly an acid stronger than abietic acid; for example, acrylic acid, acetic acid, propionic acid, benzoic acid) and an organic solvent (for example, xylene, benzyl acetate, methyl .alpha.-hydroxyisobutyrate, cyclohexanone, methyl .beta.-methoxyisobutyrate), and if necessary it further contains a monohydric alcohol, a surfactant and a corrosion inhibitor. Rinsing is preferably performed after the cleaning, using a solvent which is miscible with the defluxing agent, in order to completely remove the acid. There is also disclosed a cleaning apparatus which may be generally used for this and other cleaning.

Defluxing agent cleaning method and cleaning apparatus

A method for bonding a chip part, having solder bumps on the underside thereof, to a base material. The method includes the steps of placing the chip part at a specific position on the base material, placing a weight on the chip part, the weight being based on the number of solder bumps mounted on the chip part and a surface tension of the solder bumps at melting, and irradiating, with an electromagnetic wave, an upper surface of the weight to transfer heat to the solder bumps through the weight and the chip, thereby melting the solder bumps and bonding the chip part to the base material.

Method of bonding a chip part to a substrate using solder bumps

Cleaning method using a defluxing agent

Growing community of inventors

Kawasaki, Japan

Nobuo Igusa