Dai-ichi Kogyo Seiyaku Co., Ltd.

Dowa Mining Co., Ltd.

Matsushita Electric Industrial Co., Ltd.

Masashi Echigo

Masami Sakuraba

Masatoshi Suehiro

Seiichi Nakatani

Tsutomu Nishimura

Nobutoshi Kawamura

Susumu Okada

Yutaka Mitsune

Shuji Saeki

A copper paste composition for low temperature firing on a ceramic substrate is comprised of inorganic components and organic vehicle components. The inorganic components mainly consist of cooper powder, cuprous oxide powder, cupric oxide powder and glass powder. The mixing ratio off the inorganic components of this composition is 100 parts by weight of copper powder, about 10 to 15 parts by weight of cuprous oxide powder, about 12 to 17 parts by weight of cupric oxide powder, and about 7 to 12 parts by weight of glass powder. The mixing ratio of the inorganic components with the organic vehicle components is about 95 to 70 parts by weight of the organic vehicle components. Also the the average particle size of the copper powder is in a range of about 0.5 to 3 .mu.m and the oxygen content of the copper powder is about 0.05 to 0.15 weight percent.

Copper paste composition

A copper conductor composition comprising a copper powder, an inorganic oxide powder, a glass powder and an organic vehicle, said copper powder having an average particle size of 0.5 to 3 .mu.m, a tap density of 3.0 to 5.0 g/cm.sup.3, and an oxygen content of 0.05 to 0.15% by weight. Zinc oxide powder and, optionally, nickel powder are used as the inorganic oxide powder. The composition which contains the copper powder having such an oxygen content as low as 0.05 to 0.15% by weight, can provide copper conductors having excellent conductor properties such as solderability, adhesive strength and matching property to resistances.

Copper conductor composition

A copper conductor composition having an improved solderability as well as a good adhesion, which comprises a copper powder, an inorganic binder and a boride or silicide of a metal such as W, Mo, Ti, Ta, Nb or Cr. The solderability is kept on a good level even if the composition is subjected to a firing operation repeatedly.

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Kyoto, Japan

Masashi Echigo