CONDUCTIVE BALL, METHOD OF FORMING ELECTRODE OF ELECTRONIC PART, ELECTRONIC PART AND ELECTRONIC EQUIPMENT

WIPO Patent Application WO/2004/105053

A1

Conductive ball part (1) is produced by applying a coating layer composed of Cu layer (3) and layer of Sn-5.5Ag alloy of noneutectic composition (2) onto approximately spherical core (4) constituted of a nonmetallic material. The conductive ball part (1) is arranged through a flux on a land of electronic part, and reflow thereof is carried out at heating temperature whose peak temperature reaches 250 to 260°C. The Sn-5.5Ag alloy of noneutectic composition is conditioned into a state in which solid phase portions and liquid crystal portions coexist to thereby attain relative reduction of fluidity with the result that an SnCu layer formed on the surface of the Cu layer (3) is fixed on the land without exposure. An electrode can be formed without exposure of the SnCu layer of relatively poor solder wettability. Joint zone of excellent electrical conduction and mechanical strength can be formed between the electronic part and a circuit board.

SUMIKAWA MASATO (JP)
MURAYAMA RINA (JP)
OGAWA MASASHI (JP)
MATSUSHITA KIYOTO (JP)

PCT/JP2004/007407

December 02, 2004

May 24, 2004

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SHARP KK (JP)
SEKISUI CHEMICAL CO LTD (JP)
SUMIKAWA MASATO (JP)
MURAYAMA RINA (JP)
OGAWA MASASHI (JP)
MATSUSHITA KIYOTO (JP)

B23K35/14; B22F1/02; B23K35/26; C22C13/00; H01L21/60; H01L23/12; H05K3/34; (IPC1-7): H01B5/00; H01L21/60; H05K3/34

JP2001220691A	2001-08-14
JP2002170427A	2002-06-14
JP2003001481A	2003-01-08
JPS5446365A	1979-04-12
JPH09134933A	1997-05-20
JPH1187391A	1999-03-30
JPH11233682A	1999-08-27
JP2003068145A	2003-03-07

Kawamiya, Osamu (IMP Building 3-7, Shiromi 1-chome,, Chuo-ku, Osaka-sh, Osaka01, JP)

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