Abstract: A superconducting circuit board is provided comprising a sintered alumina board containing more than 99% by weight of alumina and an interconnection pattern of an superconducting ceramics formed on the alumina board. Adhesion of the interconnection pattern to the alumina board is improved by an addition of Ti or Si coupling agent to a paste for forming the interconnection pattern. The use of copper powder in place of copper oxide powder as an ingredient forming a superconducting ceramics in the paste is advantageous for printing and obtaining a uniform superconducting ceramic pattern.

Abstract: A laminated multi-layer wiring board comprising alternate layers of a glass ceramic material and conductor pattern. The glass ceramic layers are made of a glass ceramic comprising glass and dispersed ceramic particles. The glass ceramic layers further contain hollow or porous silica glass spheres dispersed in the glass ceramic. The hollow or porous silica glass spheres are covered with a ceramic coating layer containing aluminum as a constituent element. Such a structure prevents crystallization of the silica spheres and the resultant rapid increase in the thermal expansion coefficient of the glass ceramic layer. The structure also procludes the formation of pores in the surfaces of the spheres.

Abstract: Methods for preparing a green sheet and a glass ceramic substrate are herein disclosed.

Abstract: A perovskite type superconductor film having a high content, almost a single phase, of the high Tc phase is formed by the steps of: depositing at least one first film of a first material (e.g., a composite oxide of Bi-Sr-Ca-Cu-O system or Tl-Ba-Ca-Cu-O system) constituting a perovskite type superconductor over a substrate; depositing at least one second film of a second material containing an oxide or element (Bi.sub.2 O.sub.3, Tl.sub.2 O.sub.3, PbO.sub.x, etc., particularly PbO.sub.x) having a vapor pressure of more than 10 .sup.-4 Pa at 800.degree. C. at least as a main component over the substrate; to thereby form a stack of the first and second films; and heat treating the stack of the first and second films to form the perovskite type superconductor film on the substrate. Further, preferred compositions of the as-deposited films or stack are determined.

Abstract: A superconducting circuit board is provided comprising a sintered alumina board containing more than 99% by weight of alumina and an interconnection pattern of an superconducting ceramics formed on the alumina board. Adhesion of the interconnection pattern to the alumina board is improved by an addition of Ti or Si coupling agent to a paste for forming the interconnection pattern. The use of copper powder in place of copper oxide powder as an ingredient forming a superconducting ceramics in the paste is advantageous for printing and obtaining a uniform superconducting ceramic pattern.

Abstract: Superconductors of the Bi-Pb-Sr-Ca-Cu-O system and Tl-Pb-Ba-Ca-Cu-O system having a high Tc phase (about 110K and about 125K, respectively, or more) at a high proportion are obtained by adding a calcium compound which forms CaO and a liquid phase at a temperature for firing the superconductors, e.g., Ca.sub.2 PbO.sub.x (x=3 or 4); or by starting form a composition represented by the formula: Bi.sub.2 Pb.sub.(n-1)/2 Sr.sub.2 Ca.sub.n Cu.sub.n+1 O.sub.b, or Tl.sub.2 Pb.sub.(n-1)/2 Ba.sub.2 Ca.sub.n Cu.sub.n+1 Ob where 2.ltoreq.n.ltoreq.10, 5.ltoreq.b.ltoreq.40.5, i.e., at a ratio of Ca:Pb=2:1.

Abstract: A coolant for use in cryogenic devices of closed cycle system which comprises a mixture of a liquid nitrogen and a fluorocarbon of the formula: C.sub.n F.sub.2n+2, wherein n is an integer of 2 to 4. The coolant, when used to cool heat generating semiconductor devices and other devices to a cryogenic temperature, exhibits an increased heat flux and thus an increased cooling capability, in addition to a simple and small structure of the cooling system, and a prevention of environmental pollution.

Abstract: A method for producing a ceramic circuit board comprising the steps of (i) forming a conductor portion of the ceramic circuit board by printing a conductive paste composition on a ceramic base plate for the circuit board and then (ii) firing the ceramic base plate and the conductive paste composition together, wherein a copper-base composition comprising a copper powder and 0.5 to 5 parts by weight, based on 100 parts by weight of copper powder, of at least one organo metallic compound capable of forming an inorganic compound or compounds, respectively, when fired in an inert atmosphere, is used as the conductive paste composition.The combined use of isopropyl tridodecylbenzene sulfonyl titanate and isopropyl triisostearoyl titanate greatly improve the flowability of the copper-base conductive paste composition.

Abstract: A multi-layer superconducting circuit substrate, including insulating layers, and interconnection patterns of a superconductive ceramic material located between the insulating layers, the patterns of the superconductive ceramic material being connected via through-holes of the superconductive ceramic material, is provided. The patterns of the superconductive ceramic material are preferably encapsulated with a metal of gold, silver, platinum or an alloy thereof.

Abstract: A method for producing a multilayer ceramic circuit board including the steps of forming a multilayer structure consisting of patterns of copper-based paste and glass-ceramic layers, the glass-ceramic layers consisting of a mixture of 10 percent to 75 percent by weight of .alpha.-alumina, 20 percent to 60 percent by weight of crystallizable or noncrystallizable glass which can be sintered at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass, based on the total weight of the glass-ceramic, blended with a binder containing a thermally depolymerizable resin; prefiring the multilayer structure in an inert atmosphere containing water vapor, the partial pressure of which is 0.005 to 0.3 atmosphere, at a temperature where the thermally depolymerizable resin is eliminated; and firing the multilayer structure in an inert atmosphere containing no water vapor at a temperature below the melting point of copper so as to sinter the glass-ceramic.

Abstract: A process for producing a multilayer ceramic circuit board with copper including the steps of:forming green sheets by doctoring a slurry which includes 100 parts by weight of glass ceramic particles, 5 to 20 parts by weight of a thermally depolymerizable resin binder, 2 to 10 parts by weight of a plasticizer, and up to 2 parts by weight of a fatty acid ethylene oxide adduct type, deflorculant. The glass ceramic includes 20 to 70% by weight of alumina, and 30 to 80% by weight of SiO.sub.2 -B.sub.2 O.sub.3 glass. The process further includes the steps of forming via holes through the green sheets, screen-printing a copper paste on the green sheets, and laminating the green sheets, thereby forming a multilayer structure and firing the multilayer structure in a non-oxidizable atmosphere.

Abstract: A method for producing a multilayer ceramic circuit board including the steps of forming a multilayer structure consisting of patterns of copper-based paste and glass-ceramic layers, the glass-ceramic layers consisting of a mixture of 10 percent to 75 percent by weight of .alpha.-alumina, 20 percent to 60 percent by weight of crystallizable or noncrystallizable glass which can be sintered at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass, based on the total weight of the glass-ceramic, blended with a binder containing a thermally depolymerizable resin; prefiring the multilayer structure in an inert atmosphere containing water vapor, the partial pressure of which is 0.005 to 0.3 atmosphere, at a temperature where the thermally depolymerizable resin is eliminated; and firing the multilayer structure in an inert atmosphere containing no water vapor at a temperature below the melting point of copper so as to sinter the glass-ceramic.

Abstract: A method for producing a multilayered glass-ceramic structure with copper-based conductors therein, includes firing a multilayered structure, in which copper-based patterns and glass-ceramic layers are alternately laminated, in an inert atmosphere containing water vapor, the partial pressure of which is from 0.005 to 0.3 atmosphere. The temperature multilayered structure is fired at a temperature at which a thermally depolymerizable resin binder, contained in the glass-ceramic green sheets, is depolymerized and eliminated, but its glass components and the copper exhibit substantially no change in their state. The method also includes raising, in an inert atmosphere without water vapor, the firing temperature at which particles of the glass components coalesce, but the metallic state of copper is not affected.

Abstract: A method of forming a ceramic circuit substrate allowing mounting of high integration density semiconductor elements. The method provides a multilayered ceramic circuit substrate having via holes formed with high accuracy and high integration density wiring patterns by forming metallic conductive balls to connect the conductive wiring patterns of upper and lower layers; a ball arranging plate having many holes placing on a green sheet uniformly in close contact; filling the holes of the plate with the embedding the conductive balls by pressure into the green sheet; and thereafter baking the green sheet individually or in a stacked layered arrangement.

Abstract: A multilayer circuit board (10) for putting semiconductor devices thereon consists of conductor layers (6, 60, 61, 62, 63) made of a metal selected from the group consisting of Au, Ag, Cu and an alloy thereof, insulating material (2, 7) made of glass-ceramic and an alumina sintered plate (1). The glass-ceramic is comprised of borosilicate glass and alumina and has a low dielectric constant and a thermal expansion coefficient approaching that of the semiconductor devices. The alumina sintered plate (1) is placed between the ground and supply voltage conductor layers (62, 63) and the signal conductor layers (60).

Abstract: Disclosed is an alumina substrate having a high density, a high degree of surface smoothness and excellent dielectric properties and a process for its manufacture. The process comprises prefiring a green sheet prepared from alumina powder at an elevated temperature, for example between 1200.degree. and 1350.degree. C., to remove combustible substances from the sheet, treating the resultant prefired substrate with an acid aqueous solution to eliminate acid-soluble and decomposable substances from the substrate, and firing the acid-treated substrate at an elevated temperature, for example between 1500.degree. and 1650.degree. C.