Abstract: A thick-film conductor, a method for forming the conductor, and a method for attaching a surface-mount circuit device to the conductor with a solder connection. The conductor is formed of a thick-film conductive ink that would normally produce a solderable conductor, but is rendered unsolderable by additions of a fine inorganic particulate material. A solderable region, preferably a pillar, is then selectively formed on the unsolderable conductor to determine the distribution and height of the solder connection on the conductor. In order to suitably affect the solderability of the conductor, the particulate material is present as a fine dispersion and in a sufficient quantity, but not in quantities that significantly affect the electrical, mechanical and processing characteristics of the conductor.

Abstract: A conductor (112), a method for forming the conductor (112), and a method for attaching a discrete circuit device, such as a bond pad, chip capacitor, chip resistor, etc., to the conductor (112) with solder connections (16). Solder connections (16) formed by the method are characterized as being accurately located on the conductor (112) and having a shape and location that achieves an adequate and uniform stand-off height for the device, and improves thermal cycle fatigue life. Such benefits are achieved by forming a nonsolderable layer (114) on a substrate (10), and then forming a solderable conductor (112) on the substrate (10) such that a first portion of the conductor (112) overlies the nonsolderable layer (114) and a second portion of the conductor (112) does not overlie the nonsolderable layer (114).

Abstract: A thick-film conductor paste and thick-film conductors formed therefrom. The conductor paste is composed of metallic particles coated with a barrier layer that reduces leaching and solder diffusion into the conductor, thereby improving the reliability of the conductor-solder bond. The barrier layer may be continuous or discontinuous, and may be applied to some or all of the metallic particles of the conductor paste.

Abstract: A conductor (112) and method for attaching a surface mount device to the conductor (112), in which solder bumps (16) formed by the method are characterized as being accurately located on the conductor (112) and having a bump height and shape that provides stress relief during thermal cycles, minimizes bridging between adjacent bumps (16), allows penetration of cleaning solutions for removing undesirable residues, and enables the penetration of mechanical bonding and encapsulation materials between the chip and its substrate (10). Such benefits are achieved by forming the conductor (112) of a nonsolderable material, on which a solderable pillar (114) is formed. The pillar (114) is selectively formed to have a shape that determines the distribution and height of the solder bump (16) on the conductor (112).

Abstract: A thick film hybrid multilayer circuit characterized by circuit components that are electrically interconnected with a multilayer structure composed of multiple layers of conductors interlaid with layers of a dielectric material in order to achieve high component density. The circuit components of the hybrid circuit are bonded to the multilayer structure with a novel soldering technique employing multiple solder compositions, which reduces the occurrence of dielectric fatigue cracking from thermal cycling. As a result, the multilayer structure exhibits significantly enhanced thermal fatigue resistance.

Abstract: A high temperature thick-film hybrid circuit is characterized by a surface-mount circuit component that is electrically interconnected with a conductor. The surface-mount circuit component of the thick-film hybrid circuit is bonded to the conductor with a soldering technique employing dual-solder layers. The dual-solder layers enable component attachment to the conductor at a temperature below the maximum processing temperature of the component, while forming a solder joint that exhibits suitable adhesion properties at temperatures in excess of 165.degree. C. The dual-solder layers can be chosen to inhibit tin diffusion from the solder, silver leaching from the conductor, and the formation of a brittle intermetallic at the solder-conductor interface.

Abstract: A thick-film conductor paste and thick-film conductors formed therefrom. The conductor paste is composed of metallic particles coated with a ceramic layer that reduces leaching and solder diffusion into the conductor, thereby improving the reliability of the conductor-solder bond. The ceramic layer may be continuous or discontinuous, and may be applied to some or all of the particles of the conductor paste.