Abstract: This invention relates to a supervisory control and data acquisition (SCADA) system in which a central station (10) sends control information to, and acquires information from remote stations (11, 12) over a wire, radio or other link. Each station comprises a tabular memory (15-18) comprising storage locations in an `x` direction for storing data relating to different elements of the second system and storage locations in a `y` direction for storing data relating to different parameters of those elements. Transmitting means are provided for transmitting a message from one unit to the other unit, said message comprising an `x` part, a `y` part and a qualifier, for reading from and writing to storage locations in the tabular memory of the other unit depending on the result of a logical operation defined by the qualifier. The tabular memory can equally be considered to have a tree-like structure.

Abstract: An electroless immersion plating process for depositing a tin-bismuth plate onto a surface formed of copper or the like comprises immersing the surface into an acidic aqueous solution comprising a tin alkane sulfonate compound, preferably tin methane sulfonate, and a bismuth alkane sulfonate compound, preferably bismuth methane sulfonate. The solution also contains thiourea in an amount effective to reduce tin at the surface. The bismuth compound is added in an amount to produce a bismuth concentration that is less than about 1.0 gram per liter. Furthermore, the ratio of tin to bismuth in the solution is at least 30 to 1, and preferably at least 50 to 1. The process deposits a dense, adherent plate composed of a tin-bismuth alloy containing at least 50 weight percent tin and preferably containing greater than 70 weight percent tin, which plate is well suited for use in microelectronic soldering operations.

Abstract: A solder paste of the type utilized in forming a solder onnectin for a microelectronic package comprises a mixture of compositionally distinct metal powders. The paste comprises a first metal powder formed of tin-bismuth solder alloy. The paste further comprises a second metal powder containing gold or silver. During reflow, the gold or silver alloys with the tin-bismuth solder to increase the melting part and enhance mechanical properties of the product connection.

Abstract: A microelectronic package comprises an integrated circuit component mounted on a substrate by solder bump interconnections formed of a lead-free, tin-base solder alloy that contains a significant copper addition. A preferred solder is composed of a tin alloy containing between about 2 and 8 weight percent copper, preferably between about 3 and 5 weight percent. In the absence of lead, it is found that precipitation of copper-containing intermetallics of the type that adversely affect tin-lead solders is reduced. Moreover, the lead-free copper-tin solder alloy exhibits a high surface tension to reduce collapse of component toward the substrate during solder reflow.

Abstract: A microelectronic package (10) comprises a printed circuit board (12) enclosed within a metal housing (14) for shielding the board from spurious electromagnetic signals. The housing includes a base (30) having side walls (36). A series of first tabs (42) are formed in the side walls and engage the upper face (16) of the printed circuit board to secure the board within the housing. The side walls also include a series of second tabs (46) that engage the edge (20) of the printed circuit board in contact with the ground plane to enhance grounding of the housing.

Abstract: An electroless immersion plating process for depositing a tin-bismuth plate onto a surface formed of copper or the like comprises immersing the surface into an acidic aqueous solution comprising a tin alkane sulfonate compound, preferably tin methane sulfonate, and a bismuth alkane sulfonate compound, preferably bismuth methane sulfonate. The solution also contains thiourea in an amount effective to reduce tin at the surface. The bismuth compound is added in an amount to produce a bismuth concentration that is less than about 1.0 gram per liter. Furthermore, the ratio of tin to bismuth in the solution is at least 30 to 1, and preferably at least 50 to 1. The process deposits a dense, adherent plate composed of a tin-bismuth alloy containing at least 50 weight percent tin and preferably containing greater than 70 weight percent tin, which plate is well suited for use in microelectronic soldering operations.

Abstract: A solder paste of the type utilized in forming a solder onnectin for a microelectronic package comprises a mixture of compositionally distinct metal powders. The paste comprises a first metal powder formed of tin-bismuth solder alloy. The paste further comprises a second metal powder containing gold or silver. During reflow, the gold or silver alloys with the tin-bismuth solder to increase the melting part and enhance mechanical properties of the product connection.

Abstract: An electronic package comprises a component mounted on a substrate, such as a printed circuit board, by a solder connection that is based upon a tin alloy containing zinc. The connection is formed to copper faying surface on the substrate, and includes a first layer formed of a zinc-free tin metal bonded to the copper surface and a second layer formed of the tin-zinc solder alloy bonded to the first layer. The first layer provides a zinc-free barrier between the copper and the tin-zinc alloy to retard zinc migration to the copper interface that would otherwise result in dezincification of the solder alloy and reduce the mechanical properties of the connection.

Abstract: A liquid crystal display device, (10 in FIG. 1) comprises a liquid crystal panel (12) and a backside illuminator (14). The liquid crystal includes pixels (36) separated by a matrix area (37). The backside illuminator comprises a waveguide (40) having a face (44) facing the backside (18) of the liquid crystal panel and including light-emitting sites (48) disposed in registration with the pixels and separated by non-emitting surface (46). During operation, light received from a suitable source (52, 54, 56) is transmitted within the waveguide to the sites and emitted to illuminate the corresponding pixels.

Abstract: An optical reflector for a polymeric waveguide mounted on a generally planar substrate is formed by a method that includes sequentially irradiating overlapping zones of a polymeric ridge using a series of intermittent laser beam flashes directed normal to the substrate. Each flash is selected to be effective to remove a layer of the ridge to a predetermined depth. Each zone has a linear leading edge and is displaced relative to the leading edge of the immediately preceding zone by a distance corresponding to the predetermined depth. Furthermore, each succeeding zone overlaps the leading edge of the preceding zone. It is surprisingly found that flashes cooperate at the leading edges to form a smooth, oblique surface that, when coated with a reflective metal film, is suited for reflecting a light signal between a path normal to the substrate and a waveguide path parallel to the substrate.

Abstract: An electrically resistive film of the type used for forming thick film resistors is formed predominantly of palladium and includes an addition of boron nitride to increase resistance, preferably in combination with tantalum oxide. A paste of palladium powder and boron nitride powder dispersed in a vaporizable vehicle is applied to a substrate and sintered to form the film. In a preferred embodiment, the substrate is a ceramic powder compact that is concurrently sintered in a co-firing process.

Abstract: A piezoelectric device, such as a surface acoustic wave filter, comprises a piezoelectric film composed of a lead zirconium titanate compound applied to a substrate formed of silicon or gallium arsenide. The device includes an intermediate film between the piezoelectric film and the substrate and composed of a lead-free zirconium titanate compound to prevent interaction between lead oxide in the piezoelectric material and the material of the substrate that would otherwise cause spalling or adversely effect the electrical properties of the substrate. The piezoelectric device is made by first applying the film of the lead-free zirconium titanate compound and thereafter applying the film of the lead zirconium titanate compound. Preferably, the lead-free zirconium titanate film is applied by sputtering and annealed to densify the material and increase the dielectric constant prior to depositing the piezoelectric material.

Abstract: A method for forming a solder bump on an integrated circuit die utilizes a terminal (12) formed of an electrically conductive, solder-wettable composite material composed of copper particles and a polymeric binder. The terminal comprises a bond pad (24) overlying a passivation layer (20) on the die and a runner section (26) connecting the bond pad to a metal contact (16). The terminal is applied to the die, for example, as an ink by screen printing, after which a body of solder alloy is reflowed in contact with the bond pad to form the bump. A preferred material for the terminal is composed of silver-plated copper particles and a resol type phenolic binder.

Abstract: In an electronic package, a solder connection for bonding faying surfaces is formed of tin-bismuth alloy comprising a tertiary metal, preferably gold or silver, in an amount effective to increase the melting temperature of the alloy and enhance mechanical properties of the connection at elevated temperatures typically encountered during operation. A process for forming the solder connection comprises applying a film of the tertiary metal onto at least one faying surface and thereafter applying tin-bismuth solder paste onto the film. Preferably, a plate of tin-bismuth alloy is first electroplated onto the faying surface, onto which the tertiary metal is plated. During heating to reflow the solder, the tertiary metal dissolves to produce a uniform liquid that forms the connection.

Abstract: A gold bump contact on an electronic component is solder bonded to a bond pad of a printed circuit board or the like utilizing a solder composed of tin-bismuth alloy. The solder is applied to the bond pad as an electroplate or a paste, after which the gold bump is superposed onto the bond pad. The assembly is heated to a first temperature to melt the solder and thereafter maintained at a temperature less than 150.degree. C. to permit the molten solder to wet the gold surface, after which the assembly is cooled to solidify the solder and complete the connection. Wetting at the relatively low temperature retards dissolution of the gold and thereby reduces formation of unwanted gold tin intermetallic compounds that tend to decrease mechanical properties of the connection.

Abstract: A metal sheet is attached to a ceramic substrate utilizing a weld pad formed of tungsten layer that is preformed onto the substrate and features a faying surface coated with a gold film. The sheet is superposed onto the gold film and scanned with a laser beam to fuse the sheet and the gold, without fusing the tungsten, thereby avoiding spalling of the metal and microcracking of the ceramic.

Abstract: A method for bonding a first ceramic element and a second ceramic element utilizes a silver powder paste composed of silver particles dispersed in a volatile vehicle. A film of the paste is applied and dried onto a faying surface of each element. The elements are assembled with the films in contact and heated to sinter the silver particles into an integral silver layer that is bonded to the faying surfaces, thereby bonding the elements together. The method is particularly well suited to manufacturing a stripline filter, wherein the sintered layer not only bonds the ceramic elements, but also forms a metallic feature, such as a resonator, of the filter.

Abstract: A solder bump interconnection (34) bonding a metal bump (30) affixed to an integrated circuit component (10) to a terminal pad (18) of a printed circuit board (12) is formed using a consumable path (24) and a solder deposit (28) applied to the path spaced part from the terminal pad. In addition to the terminal pad, the printed circuit board includes a solder-nonwettable surface (21). The consumable path extends from the terminal pad on the solder-nonwettable surface and is formed oa solder-soluble metal. The solder deposit is heated, preferably by a laser beam, to form molten solder that is drawn along the pathdissolving the path as it proceeds. At the terminalmolten solder wets the pad and the metal bump and solidifies to complete the inerconnection.

Abstract: A method for forming a solder bump on an integrated circuit die utilizes a terminal (12) formed of an electrically conductive, solder-wettable composite material composed of copper particles and a polymeric binder. The terminal comprises a bond pad (24) overlying a passivation layer (20) on the die and a runner section (26) connecting the bond pad to a metal contact (16). The terminal is applied to the die, for example, as an ink by screen printing, after which a body of solder alloy is reflowed in contact with the bond pad to form the bump. A preferred material for the terminal is composed of silver-plated copper particles and a resol type phenolic binder.

Abstract: A palladium paste is utilized for forming a palladium film on a ceramic substrate. The paste includes a sinterable palladium powder dispersed in a vaporizable liquid vehicle. The paste also includes minor additions of titanium dioxide powder and a metal titanate powder. A preferred titanate powder is composed of strontium calcium titanate. It is found that the additions remarkably improve adhesion of the palladium film to the substrate.