Senju Metal Industry Co., Ltd.

Shigeki Kondoh

Masato Tsuchiya

Hiroki Sudo

Hiroshi Okada

Hiroyoshi Kawasaki

Takahiro Roppongi

Daisuke Soma

Daisuke Souma

Takashi Yashima

Hiroyuki Iwamoto

A core material has a core; a solder layermade of a (Sn—Bi)-based solder alloy provided on an outer side of the core; and a Sn layerprovided on an outer side of the solder layer. The core contains metal or a resin. When a concentration ratio of Bi contained in the solder layeris a concentration ratio (%)=a measured value of Bi (% by mass)/a target Bi content (% by mass), or a concentration ratio (%)=an average value of measured values of Bi (% by mass)/a target Bi content (% by mass), the concentration ratio is 91.4% to 106.7%. The thickness of the Sn layeris 0.215% or more and 36% or less of the thickness of the solder layer

Core material, electronic component and method for forming bump electrode

A core material has a core; a solder layer provided outside the core and being a solder alloy containing Sn and at least any one element of Ag, Cu, Sb, Ni, Co, Ge, Ga, Fe, Al, In, Cd, Zn, Pb, Au, P, S, Si, Ti, Mg, Pd, and Pt; and a Sn layer provided outside the solder layer. The solder layer has a thickness of 1 &#x3bc;m or more on one side. The Sn layer has a thickness of 0.1 &#x3bc;m or more on one side. A thickness of the Sn layer is 0.215% or more and 36% or less of the thickness of the solder layer.

The Cu core ball contains a Cu ball and a solder layer for covering a surface of the Cu ball. The Cu ball contains at least one element selected from Fe, Ag, and Ni in a total amount of 5.0 or more to 50.0 ppm by mass or lower, S in an amount of 0 or more to 1.0 ppm by mass or lower, P in an amount of 0 or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% or higher and 99.9995% by mass or lower, and sphericity which is 0.95 or higher. The solder layer includes Ag in an amount of more than 0 to 4.0% by mass or less, Cu in an amount of more than 0 to 3.0% by mass or less, and remainder of Sn.

Cu core ball, solder joint, solder paste and formed solder

The Cu core ball contains a Cu ball and one or more metal layer for covering a surface of the Cu ball, each layer including one or more element selected from Ni, Co, Fe and Pd. The Cu ball contains at least one element selected from Fe, Ag, and Ni in a total amount of 5.0 or more to 50.0 ppm by mass or lower, S in an amount of 0 ppm by mass or more to 1.0 ppm by mass or lower, P in an amount of 0 ppm by mass or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% by mass or higher and 99.9995% or lower, sphericity which is 0.95 or higher and a diameter of 1 &#x3bc;m or more to 1000 &#x3bc;m or lower.

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Tochigi, Japan

Shigeki Kondoh