Senju Metal Industry Co., Ltd.

Nitta Corporation

Takeo Saitoh

Kaichi Tsuruta

Manabu Muraoka

Takashi Hagiwara

Hiroyuki Yamasaki

Hiroki Oshima

Naoto Kameda

Kota Kikuchi

Takashi Obayashi

Shigeyuki Sekine

Masato Shiratori

Tomohisa Kawanago

Takahiro Nishizaki

Shinichiro Kawahara

Koji Yamashita

A solder ball according to the present invention contains 0.2 to 2.2% by mass of Zn, and a balance of Sn, and has a spherical diameter of 0.1 to 120 &#x3bc;m and a yellowness (b*) in an L*a*b* color system of 2.70 or more and 9.52 or less. An oxide film is formed by performing aging treatment. By producing a solder ball having a yellowness of 2.70 or more and 9.52 or less, it is possible to suppress the growth of a CuSn layer and/or a Cu&#x2014;Zn(&#x2014;Sn) layer during joining.

Solder ball, solder joint, and joining method

A flux applying device for applying flux to a surface of solder, wherein the flux applying device includes: a dipping means that applies the flux to the surface of the solder by dipping the solder into the flux; a load applying means that applies a predetermined load to the solder, the load applying means being provided at a upstream side of the dipping means; a constant speed conveying means that conveys the solder at a predetermined speed with being under load by the load applying means; a drying means that dries the solder to which the flux is applied; a cooling means that cools the dried solder; a conveying speed measurement means that measures a conveying speed of the solder; and a control means that controls the conveying speed of the solder.

Flux applying device

In the flux applying device, a control portion controls conveying rollers or the like so that thickness of flux applied to solder is controlled. The winding roller rotates so that the solder is conveyed at the conveying speed. The drawing-out roller applies any load (back tension) to the solder backward along the conveying direction of the solder when drawing out the solder. The solder is conveyed at the predetermined speed and dipped into the flux tank containing flux. The solder is pulled up from the flux tank at the conveying speed vertically. By pulling up the solder from the flux tank at the constant conveying speed vertically, the interfacial tension acts on the solderand the flux, so that the flux having a uniform thickness according to the conveying speed remains on the surface and back surface of the solder.

Liquid coating device

Provided is a solder transfer sheet which is capable of increasing the amount of solder to be transferred without the occurrence of bridging. A solder transfer sheetA includes a base material, an adhesive layerformed on the surface of the base material, a solder powder-containing adhesive layerformed on the surface of the adhesive layer, and a solder powder layerformed on the surface of the solder powder-containing adhesive layer. In the solder powder layer, particles of solder powderare arranged in a one-layer sheet form. In the solder powder-containing adhesive layer, solder powderand an adhesive componentare mixed so as to have such a thickness that two or more layers of the solder powderare stacked.

Solder transfer sheet, solder bump, and solder precoating method using solder transfer sheet

Growing community of inventors

Tochigi, Japan

Takeo Saitoh