Abstract:
A soldered assembly such as a packaged semiconductor chip includes elongated solder columns connected to the pads on the chip and a dielectric sheet having pads connected to the distal ends of the solder columns remote from the chip. Terminals on the sheet are connected to the pads of the sheet. The assembly can be handled and mounted using conventional surface-mount techniques, but provides thermal fatigue resistance. The solder columns may be inclined relative to the chip surface, and may contain long, columnar inclusions preferentially oriented along the lengthwise axes of the columns.
Abstract:
An insulating varnish comprising a resin component, electrical insulating whiskers, and if necessary, one or more additives such as an ion adsorbent, and/or an organic reagent for preventing injury from copper, produced by adding the additives to the resin component and the whiskers, or filtering the whiskers, or milled by using a beads mill or a three-roll mill, or the like, is excellent for producing a multilayer printed circuit board having high wiring density, high reliability and excellent other electrical properties.
Abstract:
A circuit board for automatically interconnecting electrical components mounted on the circuit board, comprising of a nonconducting emulsion layer sandwiched between two nonconducting outer layers. Electrical leads from electronic components are inserted through holes in one outer layer. Dispersed within the emulsion layer are conducting particles with an elongated length. The emulsion layer's melting temperature is lower than the outer layers allowing movement of the conducting particles when the temperature of the emulsion layer is above the melting temperature, and prevents movement when the temperature is below. Included with the circuit board is an electromagnetic and infrared (EIR) assembly positioned near the outer layer opposite the layer with the electronic components. The EIR assembly has an infrared source and two magnetic field generating devices. One produces a magnetic field parallel to the emulsion layer forcing the conducting particles to line up parallel to the emulsion layer. The elongated length is sufficient so each parallel positioned conducting particle comes into contact with any neighboring parallel positioned particle, thus forming a conducting path. The other produces a magnetic field perpendicular to the emulsion layer forcing the conducting particles to line up perpendicular, electrically isolating the conducting particles from any neighboring particles. Moving the EIR assembly across the circuit board generating the parallel magnetic field forms a conducting path, or generating the perpendicular magnetic field erases any conducting paths. The infrared source is used to raise the temperature of the emulsion layer.
Abstract:
A method of making electrical connections between large-scale integrated cuit boards or the like using a plastic adhesive charged with conductive particles. The method includes the steps of: coating one board with the adhesive, placing another board on the adhesive coating, applying a field to make the conductive whiskers align perpendicular to the boards, and hardening the adhesive while the field is applied. The field may be electric or magnetic, depending on whether the whiskers are paramagnetic or ferromagnetic.
Abstract:
The present invention relates to a printed circuit board arrangement (400) and a method for forming an electrical connection at a printed circuit board. The printed circuit board arrangement comprises a printed circuit board (410) having a first side (411), a second side (412) and an electrical connection (413) electrically connecting a first conductive layer and a second conductive layer (417) of the printed circuit board. The electrical connection (413) comprises a passage (416) extending from an opening in one of the sides of the printed circuit board through the printed circuit board between the first and second layers. Electrically conducting material (414) is formed on the walls (415) of the passage. The electrically conducting material forms a first path electrically connecting the first conductive layer (417) with the second conductive layer (417). At least one first ball 420 is enclosed by the passage. The at least one firstball is electrically conducting and has a diameter which is equal to or smaller than the length and diameter of the passage, wherein the at least one first ball (420) form part of a second electrical path between the first and second conductive layers of the printed circuit board, said second electrical path having a lower resistance than the first path.
Abstract:
Methods for gravure printing of transparent conductive films comprising metal nanowires. Such films exhibiting low resistivity and superior coating uniformity may be used in electronic or optical articles. When the gravure cell opening size approches the average wire length distribution, the gravure cells can behave like an effective filter that allows only small amounts of short wires to be incorporated into the grooves. Use of gravure cells with larger cell opening sizes can allow nanowires to enter gravure cells without such severe skewing of the wire size distribution in the cells.