Sumitomo Electric Industries, Limited

Yoshie Tani

Masatoshi Majima

Keiji Koyama

Shinji Inazawa

Hideki Kashihara

Masamichi Yamamoto

Jun Yorita

Hideaki Toshioka

Misako Osoegawa

An object of the present invention is to provide a new method for producing a fine metal powder, in which high purity fine metal powders which are more minute than ever before, are uniform in particle diameter, and contain no impurities can be produced at lower cost, in larger amounts, and in safety, characterized by subjecting a solution containing tetravalent titanium ions and having a pH of not more than 7 to cathode electrolytic treatment to reduce parts of the tetravalent titanium ions to trivalent titanium ions, to prepare a reducing agent solution containing both the trivalent titanium ions and the tetravalent titanium ions, and adding a water-soluble compound of at least one type of metal element forming the fine metal powder to the reducing agent solution, followed by mixing, to reduce and deposit ions of the metal element by the reducing action at the time of oxidation of the trivalent titanium ions to the tetravalent titanium ions, to produce the fine metal powder.

Method for producing fine metal powder

An anisotropic conductive film, and its production method, especially suitable for mounting a semiconductor package and sufficiently satisfying the requirements of higher density mounting because short circuit does not occur in the plane direction of the film even if the pitch of electrodes is small, or suitable for mounting a contact probe because conductive connection not fused with a high current can be ensured with a lower pressure and even a high frequency signal can be dealt with. The anisotropic conductive film contains metal powder having such a shape that many fine metal particles are linked as a conductive component, wherein the length of the chain of metal powder is set not longer than the distance between adjacent electrodes being bonded conductively when a semiconductor package is mounted, and the diameter of the chain is set in the range of 1 &#x3bc;m-20 &#x3bc;m when a contact probe is mounted. At least a part of the film is formed while orienting a chain formed of a paramagnetic metal with a magnetic field.

Anisotropic conductive film and method for producing the same

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Osaka, Japan

Yoshie Tani