Abstract: A tin-lead solder alloy containing copper and optionally silver as its alloying constituents. The solder alloy consists essentially of, by weight, about 55% to about 75% tin, about 11% to about 44% lead, up to about 4% silver, nickel, palladium, platinum and/or gold, greater than 1% to about 10% copper, and incidental impurities. The solder alloys contain a small portion of CuSn intermetallic compounds, and exhibit a melting mechanism in which all but the intermetallic compounds melt within a narrow temperature range, though the actual liquidus temperature of the alloys may be considerably higher, such that the alloys can be treated as requiring peak reflow temperatures of about 250° C. or less. The intermetallic compounds precipitate out to form a diffusion barrier that increases the reliability of solder connections formed therewith.

Abstract: A conductive adhesive material characterized by metallurgical bonds between electrically-conductive particles dispersed in a polymer matrix of the material. The polymer matrix has a fluxing capability when heated to reduce metal oxides on the surfaces of the particles. At least the outer surfaces of the particles are formed of a fusible material, so that sufficiently heating the conductive adhesive material will reduce metal oxides on the particles, and at least partially melt the fusible metal, enabling the particles to metallurgically bond to each other and to metal surfaces contacted by the adhesive material.

Abstract: A process for underfilling a bumped die surface using a lamination step and compound film such that solder bumps on the die are exposed during lamination. The compound film comprises a first layer containing an underfill material and a second layer on the first layer. The underfill material and the second layer comprise polymer materials that differ from each other. The compound film is laminated to the die, preferably at the wafer level, so that the underfill material is forced between the solder bumps and fills spaces between the bumps but does not cover the bumps. In contrast, the second layer covers the solder bumps, but is then selectively removed to re-expose the solder bumps and the underfill material therebetween.

Abstract: A no-flow underfill material and process suitable for underfilling a bumped circuit component. The underfill material initially comprises a dielectric polymer material in which is dispersed a precursor capable of reacting to form an inorganic filler. The underfill process generally entails dispensing the underfill material over terminals on a substrate, and then placing the component on the substrate so that the underfill material is penetrated by the bumps on the component and the bumps contact the terminals on the substrate. The bumps are then reflowed to form solid electrical interconnects that are encapsulated by the resulting underfill layer. The precursor may be reacted to form the inorganic filler either during or after reflow.

Abstract: A tin-lead solder alloy containing copper and optionally silver as its alloying constituents. The solder alloy consists essentially of, by weight, about 55% to about 75% tin, about 11% to about 44% lead, up to about 4% silver, nickel, palladium, platinum and/or gold, greater than 1% to about 10% copper, and incidental impurities. The solder alloys contain a small portion of CuSn intermetallic compounds, and exhibit a melting mechanism in which all but the intermetallic compounds melt within a narrow temperature range, though the actual liquidus temperature of the alloys may be considerably higher, such that the alloys can be treated as requiring peak reflow temperatures of about 250° C. or less. The intermetallic compounds precipitate out to form a diffusion barrier that increases the reliability of solder connections formed therewith.

Abstract: A conductive adhesive material characterized by metallurgical bonds between electrically-conductive particles dispersed in a polymer matrix of the material. The polymer matrix has a fluxing capability when heated to reduce metal oxides on the surfaces of the particles. At least the outer surfaces of the particles are formed of a fusible material, so that sufficiently heating the conductive adhesive material will reduce metal oxides on the particles, and at least partially melt the fusible metal, enabling the particles to metallurgically bond to each other and to metal surfaces contacted by the adhesive material.

Abstract: A new elbow canister fuseholder is provided that includes an electrically insulated and shielded housing for placing a fuse in-line between a cable and an electrical apparatus for underground distribution application. An insulating tube is contained within the housing for easy sliding removal of the fuse through an end plug such that the elbow is reusable when a fuse is replaced.

Abstract: A solder bumping method and structure for fine solder bump pitches. The method makes use of a semiconductor device having an input/output pad whose surface is provided with a solderable metal layer that serves as the UBM of the solder bump. A sacrificial layer is formed on the surface of the device to surround the metal layer. A plating seed layer is then formed on the metal layer and the surrounding surface of the sacrificial layer, after which a mask is formed on the seed layer and a via is defined in the mask to expose portions of the seed layer overlying the metal layer and the sacrificial layer. A solder material is deposited on the seed layer exposed within the via. The mask is then removed, followed by removal of a portion of the seed layer that is not covered by the solder material, leaving intact that portion of the seed layer beneath the solder material.

Abstract: A new elbow canister fuseholder is provided that includes an electrically insulated and shielded housing for placing a fuse in-line between a cable and an electrical apparatus for underground distribution application. An insulating tube is contained within the housing for easy sliding removal of the fuse through an end plug such that the elbow is reusable when a fuse is replaced.

Abstract: A method for solder bumping a surface-mount circuit component, as well as electrically and mechanically connecting the component to a conductor on a substrate, and the components and assemblies formed thereby. The method generally entails forming a multilayer metal bump containing discrete layers, including at least one layer of a solder alloy, a first metallic layer having a sufficiently high melting point so as not to melt or deform at the reflow temperature of the solder alloy, and a second metallic layer containing at least one metal that is soluble in the solder alloy. During reflow, the first metallic layer does not collapse, while the solder layer and the second metallic layer readily flow and subsequently bond the first metallic layer to suitable structures on the component and substrate.

Abstract: An encapsulated fuse assembly with a corona shield for use in high voltage underground power distribution systems. The fuse assembly includes a fuse encapsulated within an insulative outer housing. The outer surface of the fuse is coated with an electrically conductive material which is in electrical connection with one of the fuse terminals and extends along the outer surface of the fuse body to a point intermediate the other terminal leaving a portion of the fuse body not coated with the conductive material. Preferably, at least the terminal of the fuse not in contact with the conductive material is enveloped by an electrically conductive insert disposed within the insulative outer housing which along with the conductive coating establish an effective corona shield around the fuse without providing an alternate electrical circuit between the fuse terminals.

Abstract: A nickel plug (31) filling an aperture in an insulating layer (30), such as polyimide, separating two metallization levels of copper wires (28, 25) is formed by an electroless process in a plating bath (solution) containing ions of hypophosphite and of nickel. In preparation for this electroless process, the copper wires (28, 25) are first plated with a nickel layer (29) by a pseudo-electroless process-that is, a process in which the copper wires (28, 25) are located in contact with an underlying extended chromium layer (14) that is placed in electrical contact (including intimate physical contact) with an auxiliary metallic member (41) that contains nickel, while both the copper wires (28, 25), the chromium layer (14), and at least a portion of the external metallic layer (41) are immersed in a plating solution likewise containing ions of hypophosphite and of nickel.