Abstract: A process for forming fine thick-film conductor patterns on a ceramic substrate which comprises the steps of forming grooves in a positive-working photoresist layer on the substrate by the photolithographic technology, filling the grooves with a conductive paste by squeezing with a squeegee, removing the photoresist layer by a wet process, and firing the remaining conductive paste pattern is improved. By the improvements, the conductive paste is squeezed into the grooves by the screen printing technique using a mask, and/or the solvent in the conducive paste consists essentially of one or more hydrocarbons, and/or the squeegee is made of a material having a flexural modulus in a range of 30-200 kgf/mm.sup.2. The formation of the grooves may be accomplished by laser beam machining; in this case a negative-working photoresist or any other soluble resin may be used to form the grooves therein.

Abstract: A thick film circuit board comprising an insulating substrate; conductor wiring layers of a conductive material containing an oxide and formed on the insulating substrate by printing and firing; a resistance layer of a resistive material having a selected sheet resistance, being chemically reactive with the oxide, and formed between and bridging the conductor wiring layers by printing and firing; and a conductive barrier layer interposed between each of the conductor wiring layers and the resistance layer to prevent chemical reaction between the oxide of the conductor wiring layers and the resistive material of the resistance layer.

Abstract: A ceramic substrate is a high-temperature fired body consisting of alumina as the main component, zirconia, and a ceramics sintering assisting agent. The assisting agent is one of yttria, calcia, magnesia, and ceria, in which yttria is added at 0.1-2 wt %, calcia is added at 0.02-0.5 wt %, magnesia is added at 0.02-0.4 wt %, and ceria is added at 0.02-0.5 wt %.

Abstract: A low-temperature fired ceramic circuit substrate fired at a temperature ranging between 800.degree. and 1,000.degree. C. includes a plurality of insulating layers each formed of a low-temperature fired ceramic, an Ag conductor layer formed internally of the substrate, an Au conductor layer formed on a surface of the substrate, and an Ag--Pd layer formed between the Ag and the Au conductor layers, the Ag--Pd layer being composed of 100 parts metal composition consisting of 70 to 95 parts Ag and 5 to 30 part Pd by weight, and 2 to 10 parts lead borosilicate glass by weight. As the result of the above composition of the ceramic circuit substrate, its fabrication process can be simplified, and a defect rate in a connection between the Ag and Au layers after repeated firing is rendered approximately zero, which ensures high reliability for the connection.

Abstract: Low-firing glass ceramic green sheets useful in the production of glass ceramic multilayer substrates are prepared from a coarse raw powder material comprising a B.sub.2 O.sub.3 -containing glass powder. The coarse raw powder material is initially subjected to wet grinding, either in an alcohol-free organic solvent in the presence or absence of an organic binder, or in an alcohol-containing organic solvent in the presence of an organic binder, until the powder is comminuted to a particle size suitable for tape casting. The wet-ground powder is slurried with an organic solvent and an organic binder, and the slurry is cast into sheets. The resulting green sheets have improved elongation and can be punched to form fine through holes with a small pitch.

Abstract: A multilayer ceramic circuit substrate having therein internal conductor patterns comprising W and/or Mo as a main component and surface conductor patterns comprising Cu as a main component formed onto a surface layer of the multilayer ceramic circuit substrate, wherein an intermediate metal layer comprising 40 to 90 wt. % of W and/or Mo and 10 to 60 wt. % of at least one element selected from the group consisting of Ir, Pt, Ti, and Cr is formed in through-holes of the surface layer and on parts of the surface layer in the vicinity of the through holes on the surface layer, whereby the internal conductor patterns and the surface conductor patterns are electrically connected through the intermediate metal layer. The alumina multilayer ceramic circuit substrate provides an excellent bonding strength and electrical conductivity between the internal conductors and the surface conductors and enables high precision wiring and miniaturization of an electronic circuit part.

Abstract: A ceramic circuit board comprises a ceramic substrate having a glaze film formed thereon, the glaze film being overlaid with a functional thin film such as a ferromagnetic film serving as a magnetic sensor, for example. The ceramic substrate is made of a low-firing ceramic material such as a glass ceramic material which can be sintered at a temperature below 1000.degree. C. by co-firing with the glaze film. Preferably, the ceramic substrate has a recess on its top surface, and the glaze film is embedded in the recess such that the difference in level between the ceramic substrate and the glaze film is 20 .mu.m or less.

Abstract: A semiconductor ceramic package includes a plurality of laminated insulator layers each formed from a ceramic. A semiconductor chip mounting portion is formed on a surface insulator layer. A power plane is formed on at least one of internal insulator layers. A ground plane is also formed on at least one of internal insulator layers. A plurality of thermal vias are formed beneath the semiconductor chip mounting portion. Each thermal via includes a first thermal via formed so as to transmit heat generated by a semiconductor chip mounted on the semiconductor chip mounting portion to the side of a back surface layer and a second thermal via formed so as to transmit the heat generated by the semiconductor chip to the side of the back surface layer. The first thermal via is connected to the power plane and the second thermal via is connected to the ground plane. The first and second thermal vias are formed to be adjacent to each other.

Abstract: A process for producing circuit substrate is prepared by preparing at least one ceramic greensheet containing glass and sinterable at a low temperature for forming the circuit substrate, and at least one unsintered transfer sheet unsinterable at a sintering temperature of the ceramic greensheet, printing a wiring pattern on the unsintered transfer sheet, stacking the unsintered transfer sheet on the ceramic greensheet to form a laminated body and thermocompressing the laminated body to form a compressed body, firing the compressed body at a sintering temperature of the ceramic greensheet to form a ceramic substrate, thereby preparing a fired body by transferring the wiring pattern on the unsintered transfer sheet to the ceramic substrate, and removing the unsintered transfer sheet from the fired body to prepare a circuit substrate.

Abstract: A semiconductor package comprises an aluminum nitride substrate having a semiconductor element mounted thereon, a lead frame junctioned to the side of the aluminum nitride substrate directly contacting the mounted semiconductor element, and a ceramic sealing member junctioned to the aluminum nitride substrate so as to seal the semiconductor element. The lead frame has a coating layer of a nonmagnetic metallic material formed in a thickness of not more than 20 .mu.m on only one of the opposite surfaces of a lead frame matrix made of a ferromagnetic metal to which a bonding wire is to be junctioned. The layer of the nonmagnetic metallic material is formed by any of such thin film forming technique as the vacuum deposition technique, the spattering technique, and the plating technique. The coating layer formed on only one of the opposite surfaces of the lead frame matrix is capable of amply curbing the resistance and the dependency of inductance on frequency.

Abstract: A sinterable aluminum nitride powder composition is prepared by adding about 0.05-10.0 parts by weight of at least one compound selected from the group consisting of calcium tungstate and calcium molybdate and optionally about 1.0-7.0 parts by weight of at least one compound selected from the group consisting of yttria, calcium oxide, and calcium carbonate to 100 parts by weight of an aluminum nitride powder prepared by the alumina reduction method without decarbonization and having a residual carbon content of about 2%-10% by weight. The resulting powdery composition is subjected to mixing and deagglomeration in a dry process so as to form a powder mixture having a bulk density of about 0.3-0.5 g/cm.sup.3, and then to decarbonization by heating in an oxidizing atmosphere. The aluminum nitride powder composition has a pressurized bulk density of about 1.50-1.75 g/cm.sup.3 as measured at a pressure of 500 kg/cm.sup.2 and an average particle diameter of about 1.0-3.0 .mu.

Abstract: A ceramic circuit substrate is fabricated by preparing ceramic greensheets for the fabrication of the ceramic circuit substrate, and unsintered ceramic sheets unsinterable at a sintering temperature of said ceramic greensheets, forming via holes in said ceramic greensheets and filling the via holes with via hole conductor paste, printing conductive patterns on the ceramic greensheets, stacking and laminating the ceramic greensheets to prepare a laminated body, placing said unsintered ceramic sheets on the uppermost layer and-on the lowermost layer of the laminated body, bonding the sheets together by thermocompression to prepare a compressed body, firing the compressed body at the sintering temperature of ceramic greensheets, and removing the unsintered ceramic greensheets, wherein said via hole conductors are only in connection with the conductive patterns at the upper and/or lower ends of each via hole conductor.

Abstract: In a ceramic lid for sealing a semiconductor device mount portion of a ceramic package substrate having a semiconductor device mounted thereon, a seal layer disposed in an outer peripheral edge portion of a lid is formed by a solder comprising 2 to 15 wt % of Bi, 2.0 to 6.0 wt % of Sn, 0.5 to 2.0 wt % of In, 0.5 to 2.0 wt % of Ag and the balance of Pb, through an Ag--Pt system underlying metallized layer. A semiconductor package comprising a semiconductor package substrate and a lid is sealed by the lid.

Abstract: A glass sealing type ceramic package comprises: a ceramic substrate having a cavity for disposing a semiconductor device therein and a glass layer on a first main surface of the ceramic substrate, a ceramic cap having a glass layer on a second main surface thereof, a plurality of lead frames supported by opposing the first and second main surfaces to each other, and the semiconductor device being hermetically sealed in the cavity by fusing the first and second glass layers. According to a feature of this invention, the first main surface of the ceramic substrate is formed by a metallized layer; the glass layer is formed on the metallized layer, leaving a narrower outer periphery of the substrate; 70 to 90% of said lead frames are connected directly to a pad of the semiconductor device by way of metal wires; and a remainder thereof is connected indirectly to the pad of the semiconductor device by way of the metallized layer.

Abstract: A multilayer ceramic substrate having improved mechanical and electrical properties and suitable for use to form a hybrid integrated circuit and a process for the manufacture thereof. The multilayer ceramic substrate has at least one layer of a first conductor based on a refractory metal as an internal conductor layer and at least one layer of a Cu-based second conductor as a surface conductor layer, wherein the second conductor layer is connected to the first conductor layer through a metallic layer formed by coating with a metalloorganics paste containing one or more metals selected from the group consisting of Pt, Pd, Ni, Cu, Au, Rh, Ru, Re, Co, and Ir followed by firing in an inert or reducing atmosphere.