A ceramic substrate includes a ceramic layer mainly formed of a glass ceramic and a conductor trace mainly formed of silver (Ag). In an adjacent region located adjacent to the conductor trace, the concentration of boron atoms (B) contained in the ceramic layer increases toward the conductor trace.

A shielded printed wiring board with electromagnetic wave shielding film on both sides thereof is produced by placing electromagnetic wave shielding films on the two sides of the printed wiring board, with ends thereof protruding past an end of the printed wiring board. The protruding ends of the electromagnetic wave shielding films are brought together, with an air gap therebetween, and an initial application of heat and pressure causes the ends of the electromagnetic wave shielding film to adhere to each other, but without completely curing adhesive resin components of the electromagnetic wave shielding films. Protective film layers are removed from the electromagnetic wave shielding films, followed by subsequent application of heat and pressure to complete cure of the adhesive resin and to remove the air gap.

An Ag.sub.2OV.sub.2O.sub.5TeO.sub.2 lead-free low-melting glass composition that is prevented or restrained from crystallization by heating so as to soften and flow more satisfactorily at a low temperature contains a principal component which includes a vanadium oxide, a tellurium oxide and a silver oxide; a secondary component which includes at least one selected from the group consisting of BaO, WO.sub.3 and P.sub.2O.sub.5; and an additional component which includes at least one selected from the group consisting of oxides of elements in Group 13 of periodic table. A total component of the principal component is 85 mole percent or more in terms of V.sub.2O.sub.5, T.sub.eO.sub.2 and Ag.sub.2O. Contents of TeO.sub.2 and Ag.sub.2O each is 1 to 2 times as much as a content of V.sub.2O.sub.5. A content of the secondary component is 0 to 13 mole percent. A content of the additional component is 0.1 to 3.0 mole percent.

A conductive paste contains at least a conductive powder, glass frit, and an organic vehicle. The conductive powder is a mixed powder of an atomized powder prepared by an atomization method and a wet reduced powder prepared by a wet reduction method and the conductive powder contains the atomized powder in the range of 5 to 40 wt %. The atomized powder is 5.2 to 9 m in average particle size and the content of a chlorine component mixed in the conductive powder is 42 ppm or less. The conductive paste is applied in the form of a line onto a glass substrate 1 and subjected to firing to form conductive films. This conductive paste can prevent glass substrates from undergoing color changes and prevent base layers for conductive films from having structural defects such as cracks.

Disclosed herein are a variety of embodiments of thick film circuits with conductive components formed using different conductive elements and related methods for forming such circuits. One embodiment consistent with the present disclosure includes a multi-level thick film circuit formed on a substrate and having a first layer disposed on the substrate. The first layer may include a first conductive component formed using a first conductive element. The first conductive element may be a precious metal. The circuit may further include a second layer having a second conductive component. The second conductive component may be formed using a second conductive element. In one embodiment, the second conductive element may be a base metal. At least a portion of the first conductive element may directly contact at least a portion of the second conductive element such that the first layer is in electrical communication with the second layer.

An Ag.sub.2OV.sub.2O.sub.5TeO.sub.2 lead-free low-melting glass composition that is prevented or restrained from crystallization by heating so as to soften and flow more satisfactorily at a low temperature contains a principal component which includes a vanadium oxide, a tellurium oxide and a silver oxide; a secondary component which includes at least one selected from the group consisting of BaO, WO.sub.3 and P.sub.2O.sub.5; and an additional component which includes at least one selected from the group consisting of oxides of elements in Group 13 of periodic table. A total component of the principal component is 85 mole percent or more in terms of V.sub.2O.sub.5, TeO.sub.2 and Ag.sub.2O. Contents of TeO.sub.2 and Ag.sub.2O each is 1 to 2 times as much as a content of V.sub.2O.sub.5. A content of the secondary component is 0 to 13 mole percent. A content of the additional component is 0.1 to 3.0 mole percent.

A silicon nitride substrate including a phase encompassed of silicon nitride particles, and intergranular phase formed from a sintering aid, wherein a separation layer is formed on the surface of a molded body including silicon nitride powder, sintering aid powder, and organic binder, by using a boron nitride paste containing boron nitride powder, organic binder, and organic solvent; the separation layer and molded body are heated; the organic binder is removed from the separation layer and molded body; subsequently molded bodies stacked with a separation layer therebetween, are sintered. Boron nitride paste contains 0.01 to 0.50% by oxygen mass and 0.001 to 0.5% by carbon mass, and c/a is within range of 0.02 to 10.00, where c is oxygen content in the powder of the boron nitride paste, and a carbon content in the degreased separation layer, which includes 0.2 to 3.5 mg/cm.sup.2 of hexagonal boron nitride powder.

A ceramic wiring board that includes a ceramic insulator and a via-conductor. The ceramic insulator includes a crystalline constituent and an amorphous constituent. The via-conductor includes a metal and an oxide. The crystalline constituent and the oxide include at least one metal element in common. A tubular region having a thickness of 5 m adjoins and surrounds the via-conductor and has a higher concentration of the metal element than the ceramic insulator.

Provided is a mother ceramic substrate that, when divided into individual substrates (ceramic substrates), can be divided to cause divided end surfaces to be perpendicular to principal surfaces of the individual substrates, and that can provide ceramic substrates with high form accuracy; an individual ceramic substrate obtained from the mother ceramic substrate; a module component including the ceramic substrate; and a method of manufacturing a mother ceramic substrate. In a mother ceramic substrate that can be divided at a predetermined position and separated into a plurality of individual substrates, a dividing groove that defines a division position is formed in a principal surface on one side, and a protruding thread is formed on a principal surface on another side at a position corresponding to a position of the dividing groove formed in the principal surface on the one side in view in a thickness direction of the mother ceramic substrate.

A conductive paste including: (A) a silver powder; (B) a glass frit; (C) an organic binder; and (D) a powder containing copper, tin, and manganese.