Matsushita Electric Industrial Co., Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Dai-ichi Kogyo Seiyaku Co., Ltd.

Dowa Mining Co., Ltd.

Tsutomu Nishimura

Seiichi Nakatani

Satoru Yuhaku

Toru Ishida

Yasuhiko Hakotani

Koji Yoshida

Takuya Ishii

Junichi Kato

Minehiro Itagaki

Kenji Yamaguchi

Masami Sakuraba

Masatoshi Suehiro

Tatsuro Kikuchi

Yukio Terada

Satoru Yuuhaku

Yasuyuki Baba

Masashi Echigo

Kiyoshi Tsune

Yoshimasa Yabu

Tsuyoshi Imakita

Yasushi Sugimura

Yoshitaka Kurimoto

Yutaka Mitsune

Toshio Iwata

Makoto Asao

A treated waste has been treated so as to prevent diffusion of a substance to be disposed, of e.g., radionuclide &ldquo;I&rdquo;, that tends to occur when the waste is disposed of in reducing environment at an ultra-deep underground. The treated waste has a low-resolution compound containing &ldquo;I&rdquo;, e.g., &ldquo;AgI&rdquo;, and a high oxygen potential agent having a higher oxygen potential than the compound, e.g., &ldquo;Fe,O,&rdquo;. Ionization of the substance to be disposed, attributable to reduction of the compound, can be suppressed over a long time.

Treated waste, method for making the same and apparatus for making the same

The present invention provides a multilayer ceramic capacitor in which electrode metal layers and dielectric ceramic layers are laminated alternately and its dielectric constant peak is present at a temperature below &minus;50&deg; C. The multilayer ceramic capacitor is at least one selected from a multilayer ceramic capacitor to be incorporated into an electric circuit in which an electric field of at least 200 V/mm is applied to dielectric layers as a DC bias electric field and an alternating current at a frequency of at least 20 kHz is superimposed and a multilayer ceramic capacitor to be incorporated into an electric circuit in which an electric field of at least 200 V/mm is applied to dielectric layers as an AC electric field. As the dielectric ceramic, a ceramic containing lead atoms whose amount is indicated by being measured in the form of PbO, which is at least 30 mol %, particularly a compound with a perovskite structure represented by ABO,is used. Thus, an inexpensive large-capacity multilayer capacitor that has thermal resistance and is stable for a high DC bias voltage and a high frequency voltage, and a low loss switching power supply using this capacitor can be provided.

Multilayer ceramic capacitor

The present invention provides an underground-environment simulator which simulates underground environment spaces used for radioactive waste disposal or the like, and has a hermetic box, wherein the carbon dioxide gas concentration inside the box can be adjusted to an optional level, and the atmosphere inside the box can be uniformly and stably maintained. In the underground-environment simulator of the present invention, a carbon dioxide gas feeding means feeds carbon dioxide gas into a circulating gas circulation which controls the atmosphere inside the hermetic box, and the concentration of carbon dioxide gas in the circulating gas is measured and adjusted to a predetermined level while oxygen is removed from the circulating gas in an oxyhydrogen reactor. Accordingly, the carbon dioxide gas concentration can be controlled within a low concentration range, and various underground environments can be accurately simulated by varying the carbon dioxide gas concentration to an optional level.

Underground-environment simulator

A multilayered glass-ceramic substrate using copper as wiring material is fabricated by a step of forming wiring patterns with Au paste for connection of semiconductor chip prepared by adding at least one of Ni powder, Pt powder and Pd powder to Au powder, and copper oxide paste mainly composed of CuO powder, on a green sheet, and burning out the organic pattern by heat treatment in air, a step of reducing the copper oxide electrode by heat treatment in a reducing atmosphere containing hydrogen, and a step of sintering the substrate material, copper oxide electrode and gold electrode by heat treatment in nitrogen. Since the Au wiring pattern is formed on the top layer of the multilayered substrate in this constitution, wire bonding of high reliability is realized. Besides, by making use of the excellent solderability of Au, it may be also applied in flip-chip mounting of semiconductor. In addition, in this Au paste composition, the melting point of Au may be raised, and alloying or fusing is avoided if sintered at 900.degree. C. together with Cu electrode.

Multilayered ceramic substrate and method of manufacturing the same

A laminated ceramic capacitor comprises a plurality of inner electrode layers for developing a capacitance, dielectric layers sandwiched with the inner electrode layers, and a pair of outer electrodes coupled to their associated inner electrode layers for output of the capacitance. The inner electrode layers are made of Ni. The dielectric layers are made of a dielectric ceramic composition having a structural formula of:

Laminated ceramic capacitor

A low temperature sintering dielectric ceramic composition, which exhibits high dielectric constant, low dielectric loss, high electrical resistivity, high mechanical strength and narrow grain size distribution, is disclosed. The ceramic composition is a binary system comprising lead magnesium niobate (Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3) and copper oxide, or a ternary system comprising lead magnesium niobate (Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3), lead titanate (PbTiO.sub.3) and copper oxide. A multilayer ceramic capacitor comprising internal copper electrodes and ceramic dielectric layers consisting of the dielectric ceramic composition is also disclosed. A method of readily manufacturing the multilayer ceramic capacitor with copper internal electrodes is also disclosed. This fabrication method comprises a stop of forming a multilayer laminate by the green tape multilayer laminating method using dielectric ceramic tapes and a conductor paste containing CuO as its main component; a step of heat-treatment for decomposing and removing organic binder in air (binder removing process); a step of reducing CuO in the internal electrode layers to copper by heat-treatment in a mixed gas atmosphere of nitrogen and hydrogen (reduction process); and a step of sintering the multilayer laminate in a nitrogen atmosphere (sintering process).

Dielectric ceramic composition and a multilayer ceramic capacitor and a

Multilayered ceramic substrates having Cu electrode patterns in or on ceramic-glass insulating layers which consist essentially of Al.sub.2 O.sub.3, SiO.sub.2, B.sub.2 O.sub.3, Na.sub.2 O, K.sub.2 O, CaO, MgO and PbO. The methods for manufacturing the substrate comprises thermally treating a laminate of alternately superimposing ceramic-glass insulating layers and CuO-based electrode layers of desired patterns in air or in a molecular oxygen-containing atmosphere to eliminate organic binders from the laminates by burning out, reducing the CuO into metallic Cu at low temperatures in an atmosphere containing hydrogen, and firing the thus reduced laminate in an inert gas such as nitrogen. The firing is effected at 850.degree. to 950.degree. C. The multilayered ceramic substrate may also be obtained by forming ceramic-glass insulating layers and CuO-based electrode layers alternately on a sintered ceramic support, followed by the thermal treatment, reduction and firing set forth above.

Multilayered ceramic substrates and method for manufacturing the same

Disclosed are a CuO conductor paste which is effective for making a multilayered ceramic body, the conductor material of which is made of copper, and a method of manufacturing a multilayered ceramic body using the conductor paste. The conductor paste is made of CuO as the main component with an addition of at least one of PbO-based glass, or any of Bi.sub.2 O.sub.3 -based glass, CuO-based glass and CuAl.sub.2 O.sub.4 as the additive. The multilayered ceramic body is manufactured by a method comprising a forming process for making a multilayered body from the conductor paste and dielectric material, a binder removing process by heat treating the multilayered body, thus obtained, in air, a reduction process for reducing CuO to copper in a mixed gas atmosphere of hydrogen and nitrogen, and a sintering process for sintering the multilayered body thus reduced in a nitrogen gas atmosphere.

Conductor composition and method of manufacturing a multilayered ceramic

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.

Copper conductor composition

Disclosed is a dielectric paste for a ceramic multilayer wiring substrate, of which feature, among others, lies in the composition of inorganic components comprised of ceramics made of Al.sub.2 O.sub.3, SiO.sub.2, CaO and MgO, and a borosilicate glass. This can be prepared by mixing a part of the glass with the ceramic, calcining the mixture at a high temperature, and then adding the remaining glass to mix with the calcined product. The insulation layer is densely formed, and a dielectric paste excelling in electric insulating property can be obtained by mixing this composition with an organic liquid.

Dielectric paste and method of manufacturing the paste

A method of manufacturing a multilayer ceramic using Cu as the conductor material is disclosed. This method comprises a step of forming a multilayer laminate by the green tape multilayer laminating method or by the thick film printing method on ceramic substrate with an insulating material with a mixture of ceramic and glass containing lead oxide as its main component and a conductor paste with CuO as its main component; a step of heat-treatment for decomposing and removing organic binder in air (binder removing process); a step of causing reduction at temperatures where copper oxide is reduced, but lead oxide is not, in a mixed gas atmosphere of nitrogen and hydrogen (reduction process); and a step of firing in a nitrogen atmosphere, thereby effecting sintering of the insulating material composed of ceramic and glass containing lead oxide and metallization of copper electrodes (firing process). For the uppermost layer electrodes, metal copper paste is employed, and a pattern printing process is conducted subsequent to the aforementioned reduction process, so that the sintering of the insulating material and the metallization of the uppermost layer are simultaneously performed; in this way, highly reliable uppermost layer Cu electrodes are obtainable.

Method of manufacturing a multilayer ceramic body

A thick film conductor composition for a ceramic wiring substrate comprises an inorganic ingredient mainly composed of a copper oxide powder added with a metal capable of forming a homogeneous solid solution with copper, and an organic vehicle. The inorganic ingredient may be further added with a manganese oxide or a heat resistant insulating material such as ceramics and/or glass.

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Uji, Japan

Tsutomu Nishimura