A highly conductive transparent glass-based circuit board includes a glass substrate. The glass substrate is a glass-tempered substrate. A surface of the glass-tempered substrate faces air. A conductive paste, printed on the surface of the glass-tempered substrate, is baked, heated, and cooled to form a conductive circuit fused with the surface of the glass-tempered substrate. The surface of the glass-tempered substrate and an upper surface of the conductive circuit are at the same level. A surface of the conductive circuit, except a region reserved for a solder pad used for welding a component, is covered with a printed-circuit-board (PCB) organic solder-resistant layer. The conductive circuit is tightly fused with the glass substrate. It is a fusional relation between the conductive circuit and the glass substrate. A surface of the glass substrate and an upper surface of the conductive circuit are at the same level. Because a surface of the highly conductive transparent glass-based circuit board is smooth, the conductive circuit is not easily damaged. The highly conductive transparent glass-based circuit board has the characteristics of high conductivity and high transmittance.

To provide a method for firing a copper paste, which improves sinterability of copper particles for the purpose of forming a copper wiring line that is decreased in the electrical conductivity. A method for firing a copper paste, which comprises: an application step wherein a copper paste is applied over a substrate; a first heating step wherein the substrate is heated in a nitrogen gas atmosphere containing from 500 ppm to 2,000 ppm (inclusive) of an oxidizing gas in terms of volume ratio after the application step, thereby oxidizing and sintering copper particles in the copper paste; and a second heating step wherein the substrate is heated in a nitrogen gas atmosphere containing 1% or more of a reducing gas in terms of volume ratio after the first heating step, thereby reducing the oxidized and sintered copper oxide.

Precision screen printing is described that is capable of sub-micron uniformity of the metallization materials that are printed on green sheet ceramic. In some examples, puck is formed with electrical traces by screen printing a paste that contains metal on a ceramic green sheet in a pattern of electrical traces and processing the printed green sheet to form a puck of a workpiece carrier. In some example, the printing includes applying a squeegee of a screen printer to the printed green sheet in a squeegeeing direction while the green sheet is on a printer bed of the screen printer. The method further includes mapping the printer bed at multiple locations along the squeegeeing direction, identifying non-uniformities in the printer bed mapping, and modifying a printer controller of the screen printer to compensate for mapped non-uniformities in the printer bed.

Precision screen printing is described that is capable of sub-micron uniformity of the metallization materials that are printed on green sheet ceramic. In some examples, puck is formed with electrical traces by screen printing a paste that contains metal on a ceramic green sheet in a pattern of electrical traces and processing the printed green sheet to form a puck of a workpiece carrier. In some example, the printing includes applying a squeegee of a screen printer to the printed green sheet in a squeegeeing direction while the green sheet is on a printer bed of the screen printer. The method further includes mapping the printer bed at multiple locations along the squeegeeing direction, identifying non-uniformities in the printer bed mapping, and modifying a printer controller of the screen printer to compensate for mapped non-uniformities in the printer bed.

Close-contact layers that are capable of improving the degree of contact between electrodes and a ceramic insulating layer can be formed at low cost by firing a glass paste. When the electrodes, the ceramic insulating layer, and the close-contact layers are fired at the same time, the glass paste is sintered last, and thus, formation of voids, defects, and the like in portions of the ceramic insulating layer, on which the electrodes are disposed, as a result of shrinkage of the electrodes and the ceramic insulating layer at the time of firing being hindered by stress generated due to the difference in the degree of shrinkage can be suppressed. Therefore, the structure of the ceramic insulating layers in the above portions can be elaborated by the close-contact layers.

A ceramic substrate according to the present disclosure includes a plurality of electrodes on an electronic component mounting surface, and one or more interelectrode wires that connect the electrodes to each other on the electronic component mounting surface. A resist that extends across the interelectrode wire is disposed on the electronic component mounting surface.

A method of manufacturing a ceramic substrate includes the steps of preparing a ceramic paste in which a powder of at least one of a metal boride and a metal silicide is added to a raw material powder of a glass ceramic, applying the ceramic paste to a green sheet which is to become a ceramic layer after firing, applying a conductor paste which is to become a conductor trace after firing to the ceramic paste having been applied to the green sheet, and firing the green sheet carrying the ceramic paste and the conductor paste applied thereto.

The present invention relates to a method for improving adhesion between ceramic and a thick film circuit. The method is particularly directed to accelerate the formation of a ceramic-metal eutectic phase between the ceramic carrier and the metal circuit by solid-phase diffusion bonding under a positive atmosphere. A metallic conductive slurry or its oxide slurry is printed on the surface of the ceramic carrier to form a circuit pattern by a thick film screen printing. The ceramic carrier is placed in an oven with temperature controlled by a program under a positive-pressure atmosphere of an inert gas including nitrogen, hydrogen or their mixtures. An eutectic phase is formed between the ceramic carrier and the metal circuit under a high temperature eutectic condition to increase the adhesion between the ceramic carrier and the thick film circuit.

The present invention provides a wiring board having a conductor portion on which mounting is suitably possible and a method for manufacturing the wiring board. Since an initial Cu plated layer is formed by plating so as to cover the surface of a metallized layer and then the initial Cu plated layer is heated to be softened or melted, copper in the softened or melted initial Cu plated layer enters into open pore portions of the metallized layer. In addition, during the heating, components of the metallized layer and components of the initial Cu plated layer are mutually thermally diffused. Consequently, when solidified later (that is, when the initial Cu plated layer becomes a lower Cu plated layer), the adhesiveness between the metallized layer and the lower Cu plated layer is improved due to, for example, an anchoring effect and a mutual thermal diffusion effect, and therefore mountability is improved.

To provide more space for additional circuit elements (coils, capacitors) and/or to allow the accommodation of additional circuit elements required for shielding the circuits, the metallization regions are arranged one over the other in at least two metallization layers. The carrier body has a surface on which sintered metallization regions are arranged in a first metallization layer, said metallization regions carrying electronic components and/or being structured such that the metallization regions form resistors or coils. The metallization regions are covered, together with the components and/or the resistors or coils, by a ceramic plate, and optionally additional metallization regions are arranged in additional metallization layers on the ceramic plate and each metallization region is covered by a ceramic plate. Sintered metallization regions are arranged in a metallization layer for the purpose of accommodating circuit elements on the uppermost ceramic plate facing away from the cooling elements.