Abstract: A multi-layer conductor system including: a base layer having an electrically insulative top portion including alumina; an electrically conductive intermediate layer formed on the top portion of the base layer; and an electrically conductive top layer formed on the intermediate layer; wherein the intermediate layer includes alumina and a precious metal alloy consisting of silver and a precious metal other than silver; wherein the top layer comprises a precious metal selected from the group consisting of silver and a silver alloy such that the difference between the percentage weight of silver in the precious metal of the top layer and the percentage weight of silver in the precious metal alloy of the intermediate layer is limited to thereby provide advantages in use.

Abstract: A multi-layer conductor system including: a base layer having an electrically insulative top portion including alumina; an electrically conductive intermediate layer formed on the top portion of the base layer; and an electrically conductive top layer formed on the intermediate layer; wherein the intermediate layer includes alumina and a precious metal alloy consisting of silver and a precious metal other than silver; wherein the top layer comprises a precious metal selected from the group consisting of silver and a silver alloy such that the difference between the percentage weight of silver in the precious metal of the top layer and the percentage weight of silver in the precious metal alloy of the intermediate layer is limited to thereby provide advantages in use.

Abstract: A thick-film paste for printing thick-film circuit elements, including solder stops, conductors, resistors and capacitors, and a method for using the paste. The paste has a composition that includes an organic vehicle, a filler material that contributes the desired electrical and/or material properties to the thick film fired from the paste, and an additive that is insoluble in the organic vehicle and contributes pseudoplastic Theological properties to the paste during printing. The additive also preferably evaporates, burns off, sublimates or is otherwise removed below the firing temperature of the paste.

Abstract: A hybrid circuit structure that includes a metal substrate, an inorganic electrical insulator layer and at least one inorganic thick-film passive circuit element, such as a thick-film resistor, capacitor or conductor. An interface layer is provided between the insulator layer and the circuit element to prevent the detrimental effects of interlayer diffusion. The composition of the interface layer is selected to prevent the diffusion of constituents from the inorganic insulator layer, and to have a CTE near that of the circuit element to reduce thermal fatigue. As a result, the passive circuit element can be formed of essentially any one of a number of conventional inorganic thick-film materials that are widely used on alumina substrates.

Abstract: An improved method of manufacturing thick film circuit wherein an IC is attached to a central conductor pad with adhesive, and wherein spreading of the adhesive is constrained by a ring of porous dielectric material formed between the central conductor pad and the peripheral conductor pads to which the IC terminals are bonded. When the adhesive material is printed and begins to spread, it contacts the porous dielectric ring, which absorbs the adhesive material and stops the spreading. In this way, the porous dielectric ring controls the dimensions of the cured adhesive, thereby preventing the adhesive from contaminating the peripheral conductor pads. Even with the addition of the intervening dielectric ring, the length of the wire-bond connections and the overall dimension of the IC and its conductor pads are both significantly decreased, contributing to improved circuit area utilization and wire-bond durability.

Abstract: 16 A thick-film circuit (10) includes an electrically conductive substrate (12), such as stainless steel, and a first layer of a gold-rich conductor (15) applied directly thereon. The gold layer is fired in a non-oxidizing atmosphere, such as nitrogen, to ensure a solid mechanical and electrical connection between the gold and the substrate. A next layer of a silver composition (20) containing a first proportion of silver to a conductive metal is directly applied to the gold layer (15). Preferably, the composition (20) includes palladium in equal parts with the silver to achieve a secure mechanical and electrical contact with the gold layer with a minimum resistivity. A silver-rich layer (23) is then applied directly onto the intermediate layer. This silver-rich layer (23) is a composition of silver and the conductive metal in a second proportion greater than the first proportion. In one embodiment, this second proportion is three parts silver to one part palladium by weight.

Abstract: An improved method of making a multiple print thick film circuit wherein the alignment between successive conductor print steps is both optically inspectable and electrically testable. The first of two or more successive conductor print layers includes a pair of adjacent alignment features with a non-conductive gap therebetween, and the successive conductor print layer includes a pair of identical alignment features which are printed directly on top of the alignment feature pair of the first print layer. When the successive print layer is properly aligned with the first print layer, the non-conductive gap between the alignment features of the first print layer will be preserved, and test probes brought into contact with the features or associated probe pads will reveal a high or open-circuit impedance therebetween.

Abstract: An improved method of manufacturing thick film circuits that effectively eliminates the trade-off between thickness and definition, permitting dielectric layers of increased thickness with no pin-holes, and at the same time, more precise definition of dielectric features, such as via openings and solder stops. The method utilizes a dielectric material that can be co-fired with an underlying conductor, and preferably, that remains porous after firing. A layer of the dielectric material (FDL) is printed atop a dried but not yet fired conductor of the first circuit layer, and then co-fired with the conductor. Spreading of the FDL prior to firing is minimized due to the porosity of the dried but unfired conductor, which absorbs solvent from the FDL. The FDL can be printed in a ring, enclosing a portion of the underlying conductor to form a via definition ring, or VDR.

Abstract: An improved method of manufacturing multi-layer thick film circuits that effectively eliminates the trade-off between thickness and definition, permitting dielectric layers of increased thickness with no pin-holes, and at the same time, more precise definition of dielectric features, such as via openings and solder stops. The dielectric features are precisely defined by an initial thin layer of dielectric material, referred to as a feature definition print, or FDP. After the FDP has been dried but not yet fired, a via can be formed by printing a comparatively thick cover layer of dielectric, over-lapping the edges of the FDP. Due to the porous nature of the dried but not fired FDP, it absorbs solvent from the dielectric cover layer, which inhibits the spreading of the dielectric cover layer. The FDP is then co-fired with the first dielectric layer, and a second dielectric layer may be provided atop the fired first layer to further increase the overall dielectric thickness, if so desired.

Abstract: A screen printing device for screen printing a thick film ink through a screen so as to form a highly-defined thick film on a surface of a microelectronics circuit. The screen printing device achieves the above by bypassing excess ink that would otherwise accumulate ahead of the squeegee device, thereby limiting the pressure lead length ahead of the device during the screen printing process. As such, the screen is able to form an adequate seal with the surface of the substrate to prevent ink from bleeding out under the screen, i.e., between the screen and substrate. The result is a well-defined thick film on the substrate, and avoids the necessity of stopping the printing operation in order to remove ink from the lower surface of the screen. The screen printing device enables a method by which well-defined films can be readily deposited at high throughput levels, without necessitating additional procedures, equipment and techniques that might otherwise further complicate the printing process.