Abstract:
A method of depositing solder paste includes the steps of: superimposing a masking member having a plurality of through-holes and a supporting member on each other so that the supporting member covers the plurality of through-holes; filling cavity portions formed by the plurality of through-holes and the supporting member with solder paste; disposing an LSI chip and the masking member so that electrodes and the cavity portions are superimposed on each other respectively; and heating the solder paste so as to make the solder paste deposit on the electrodes.
Abstract:
A process within substrate is provided with vias communicating with surface contacts or bumps. Joining material paste is forced through holes in a screen onto an area array of the contacts on the substrate then the screen is biased against the substrate as the paste is heated and cooled to transfer the joining material onto the contacts. Alternately, joining material paste is forced into the screen and then a substrate is placed onto the screen with an area array of bump contacts of the substrate in contact with the solder paste, and then the paste is heated and cooled to transfer the material onto the bumps. The joining material may be a solder paste, conductive adhesive paste, or transient liquid bond paste. The substrate may be a semiconductor chip substrate, flexible or rigid organic substrate, or a metal substrate coated to form a dielectric surface. Also, the substrate may be a computer chip, chip carrier substrate or a circuit board substrate. The process may be used to produce flip chips, ball grid array modules, column grid array modules, circuit boards, and attachment structures of the preceding components including information handling systems.
Abstract:
A flexible wiring board includes a printed conductive circuit layer formed on an insulating film, a metallic layer formed on the printed conductive circuit layer, and an insulating layer formed on the metallic layer. A method of making a flexible wiring board includes the steps of forming a conductive circuit layer by screen printing a wiring pattern using a conductive paste, baking the printed wiring pattern, and forming a metallic layer on the printed conductive circuit layer by a plating method.
Abstract:
A method for forming a conductive vias in a non-conductive substrate having a through-hole formed therein intermediate two side thereof. The method utilizes the steps of: applying gold paste to the through-hole so as to provide electrical conduction therethrough; and under firing the gold paste when a thin conductive film is present upon the substrate and fully firing the gold paste when no thin conductive film is present on the substrate. Under firing the gold paste when a thin-film is present upon the substrate prevents degradation of the thin conductive film. Subsequent processing of the gold paste assures the integrity and reliability thereof. Thus, the gold paste provides enhanced conductivity and improved reliability, as compared to contemporary thin-film vias.
Abstract:
In a ceramic multi-layer wiring board, a surface conductor layer is made of a copper-based material and an inner conductor in the ceramic multi-layer is a non-copper metal having a melting point higher than a temperature at which the ceramic multi-layer is fired, typically Ag. Cu and Ag form eutectic crystals when firing the surface conductor layer of Cu. This can be prevented by connecting the surface conductor layer and the inner conductor with Ag--Pd or a metal which is different from the materials of the surface wiring layer and the inner conductor and which does not form eutectic crystals with the material of the surface wiring layer at the temperature at which the surface wiring layer is fired.
Abstract:
Disclosed is an aluminum nitride body having graded metallurgy and a method for making such a body. The aluminum nitride body has at least one via and includes a first layer in direct contact with the aluminum nitride body and a second layer in direct contact with, and that completely encapsulates, the first layer. The first layer includes 30 to 60 volume percent aluminum nitride and 40 to 70 volume percent tungsten and/or molybdenum while the second layer includes 90 to 100 volume percent of tungsten and/or molybdenum and 0 to 10 volume percent of aluminum nitride.
Abstract:
A process for fabricating a plurality of solder joints from a low melting point solder paste and high melting point solder balls is described. An abbreviated process flow is as follows: First, the solder balls are placed into cavities in an alignment boat, a vacuum is initiated to hold the boat and solder balls in place. Second, an amount of solder paste is applied directly onto the solder balls in the boat. Third, an alignment plate is placed over the alignment boat to provide a means of roughly aligning the solder ball/solder paste combination to the substrate. Fourth, the substrate is placed through the alignment plate on top of the solder balls in the boat. Pressure is applied to wet the solder paste to the conductive pads on the substrate. Finally, the substrate and alignment boat assembly is processed through a furnace for solder paste reflow. No expensive alignment tools are necessary as the substrate can at least partially realign itself to the array of solder balls during reflow because of the surface tension exerted by the molten solder paste as it wets the entirety of each conductive pad on the substrate.
Abstract:
A method of manufacturing and monitoring the manufacture of a thick film circuit board device. The method includes the steps of forming a resistive layer in a prescribed pattern on an insulative base board, forming a first conductive layer on the insulative base board adjacent to the resistive layer with a gap of predetermined width therebetween and forming a second conductive layer in the gap and overlapping a portion of the resistive layer and the first conductive layer for establishing electrical contact between the resistive layer and the first conductive layer.
Abstract:
A printed circuit board comprises a base plate and a circuit conductor formed on at least one of the opposed surfaces of the base plate. A heat-radiating film is formed on at least a portion of the surface of the circuit conductor, and an insulating film is formed over the exposed surfaces of the heat-radiating film and the circuit conductor. At least one opening is formed in the insulating film, and the opening overlies the heat-radiating film thereby directly exposing the heat-radiating film to ambient atmosphere so as to promote dissipation of heat from the circuit conductor during use of the printed circuit board. The opening in the insulating film may be in the form of a slot or may comprise a pattern of circular or oval openings. The heat-radiating film may be copper or nickel paste, or non-organic material such as aluminum oxide.
Abstract:
A process for producing an hermetic feedthrough in a ceramic substrate by providing a sheet of liquid phase sinterable ceramic composition having a feedthrough hole, filling the feedthrough hole with refractory metal metallization material, firing the resulting structure to produce a sintered substrate and adherent metallization wherein the metallization is comprised of continuous phases of refractory metal and glass, contacting the refractory metal with electrically conductive intrusion metal and heating the resulting structure to a temperature at which the glassy phase is fluid, the refractory metal is solid, and the intrusion metal is liquid whereby the liquid metal preferentially wets the refractory metal, migrates into the metallization displacing glass and, upon subsequent solidification, partially or wholly occupies the volume space originally containing the continuous glass phase.