Narumi China Corporation

Kao Soap Company, Ltd.

Sumitomo Metal (smi) Electronics Devices, Inc.

Daiken Chemical Co., Ltd.

Junzo Fukuda

Susumu Nishigaki

Shinsuke Yano

Masashi Fukaya

Katsuhiko Kita

Hiroshi Kawabe

Akio Harada

Hidemasa Ohmura

Osamu Nakagawa

Shiro Kawahito

Takeya Sakai

A thick film paste for use in the formation of a conductor, a resistor, an insulator, a protector or the like in a ceramic wiring substrate by a printing process, wherein at least 2-tetradecanol as a solvent is contained in an amount of at least 3% by weight. The thick film paste is excellent in printability, for example, has less viscosity change during printing and exhibits less bleeding.

Thick film paste

A multilayer ceramic substrate with multilayered circuit patterns, the improvement in which internal conductors for wiring are formed by a Ag base conductive materials capable of being co-fired with multilayered green ceramic substrate sheets in an oxidizing atmosphere and external conductors electrically connected with the internal conductors are formed by a Cu base conductive material, the external Cu conductors being formed in such a manner so that a liquid phase of Cu-Ag is not formed at the interface of the Cu conductor and the Ag conductor. Further high reliable resistors of RuO.sub.2 or Bi.sub.2 Ru.sub.2 O.sub.7 type may be integrally formed onto and/or inside the substrate. In such an arrangement, problems or difficulties caused due to Ag migration, incomplete binder removal, solder leaching, etc., are eliminated and thereby there can be a multilayer substrate with a high reliability and a high pattern precision.

Multilayer ceramic substrate with circuit patterns

In a multilayer ceramic circuit board comprising a substrate, an insulating layer on the substrate, and a conductive pattern on the insulating layer, an additive of Cr.sub.2 O.sub.3 or MnO.sub.2 is added to the insulating layer to reinforce adhesion between the insulating layer and the conductive pattern. Each of the substrate and the insulating layer is manufactured by firing at a temperature between 800.degree. C. and 1000.degree. C., alumina particles and a glass composition comprising an alumina component. When a total amount of alumina in the substrate is equal to or greater than that in the insulating layer, an amount of Cr.sub.2 O.sub.3 or MnO.sub.2 is restricted to a range between 0.1% and 10.0% by weight, with a difference between the total amounts of alumina falling within a range between 0% and 30% by weight. When the total amount of alumina in the substrate is smaller than that in the insulating layer, the amounts of Cr.sub.2 O.sub.3 and MnO.sub.2 may be between 0.1% and 10.0% by weight and between 0.1% and 15% by weight, respectively. The difference between the total amounts of alumina may be between 0% and 20% by weight.

Multilayer ceramic circuit board fired at a low temperature

Low temperature fired ceramics are produced by a highly improved method, using a specially designed apparatus and the obtained ceramic products are very useful in various applications, such as electronic components, heat resistant articles, tablewares, kitchen utensils or decorative articles because of a combination of superior properties, particularly high heat resistance, high mechanical strength, low thermal expansion and low dielectric constant. In practicing the method, a low firable ceramic material is shaped into a green sheet and then converted to a dense fired ceramic product by rapid firing in an adequate air. In the firing step, the air feed ratio (the ratio of the quantity of feed of air to the theoretical quantity of air required for combustion) is controlled so as to be at least 1.5 thereby the aimed fired products can be obtained in a greatly reduced firing time, without causing deformation or warpage of the ceramics or ignition of the decomposition gases of a binder.

Method for manufacturing low temperature fired ceramics

In an article comprising a ceramic body fired at a comparatively low temperature and a circuit pattern attached to the body, the ceramic body is produced from a preselected composition comprising first powder of alumina and second powder of a vitreous material which comprises any one of MgO-Al.sub.2 O.sub.3 -SiO.sub.2, CaO-MgO-Al.sub.2 O.sub.3 -SiO.sub.2, CaO-Al.sub.2 O.sub.3 -SiO.sub.2 glass, CaO-Al.sub.2 O.sub.3 -SiO.sub.2 -B.sub.2 O.sub.3 glass, MgO-Al.sub.2 O.sub.3 -SiO.sub.2 -B.sub.2 O.sub.3 glass, and CaO-MgO-Al.sub.2 O.sub.3 SiO.sub.2 -B.sub.2 O.sub.3 glass. The ceramic body comprises coexistence of an alumina part, a noncrystallized part, and a crystallized part and exhibits an excellent moisture proof. The circuit pattern comprises an internal conductive pattern of Ag and an external conductive pattern of an alloy of Ag-Pd. A chromium component may be included in the internal and the external conductive patterns. External and internal resistor patterns are placed on and within the ceramic body with a high and a low precision. The internal resistor pattern can be adjusted by the use of a laser beam through a thin film included in the ceramic body.

Ceramic article having a high moisture proof

A method of preparing green ceramic tapes, comprising adding to 100 parts by weight of a fine ceramic powder, 2 to 15 parts by weight, in terms of its resin content, of a binder mixture consisting of an aqueous polyurethane and a water-soluble acrylic resin, the amount of said water-soluble acrylic resin ranging from 10 to 1500 parts by weight per 100 parts by weight of said aqueous polyurethane in said binder mixture, adding a small amount of a dispersing agent to the mixture followed by a sufficient amount of water, kneading the resultant mixture for a time sufficient to prepare an aqueous slip, forming a tape in a known manner from said aqueous, and then drying the green tape obtained.

Method of producing ceramic tapes

Green ceramic tapes are prepared which comprise a finely divided ceramic powder and a water-compatible polyurethane resin binder. The green tapes are prepared by casting a water-based slip containing the ceramic powder and the water-compatible polyurethane resin binder in the form of the tape and then drying the formed tape. The drying is preferably conducted in two stages, in the first of which a relatively humid atmosphere is maintained.

Growing community of inventors

Nagoya, Japan

Junzo Fukuda