Abstract: An electrical connection for a surface-mount circuit device, and a method for forming the electrical connection. The electrical connection includes a solder stop that promotes the accurate location of a solder joint that electrically connects the surface-mount device to the conductor. In accordance with the invention, the solder stop also promotes stress relief of the electrical connection during thermal cycling, such that thermal cycle fatigue cracking occurs in the solder stop instead of the conductor and solder joint. As a result, thermal stresses are absorbed and dissipated by the solder stop, and do not adversely affect the continuity and mechanical integrity of the electrical connection. The solder stop preferably has a composition that contains an inorganic particulate filler in a glass matrix, the latter being present in an amount that forms a weak bond between the inorganic particles and between the solder stop and conductor.

Abstract: A conductor pad, formable on a substrate or a printed circuit board, for conducing the reduction of gas voids in solder when an electronic device is soldered to the conductor pad, wherein the conductor pad includes a uniform and electrically conductive base layer having an interface surface, and also includes a patterned layer formed on the interface surface of the base layer, wherein one of the base layer and the patterned layer is substantially non-wettable and the other is substantially wettable, and wherein the base layer and the patterned layer cooperatively define strips of non-wettable surface areas which extend across the interface surface of the base layer. The strips of non-wettable surface areas can be defined upon the interface surface of the base layer in various ways to thereby create various non-wettable patterns upon the base layer. Preferably, the base layer is substantially wettable, and the patterned layer is both substantially non-wettable and electrically conductive.

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: 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: 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.