Abstract:
A method of creating domed shaped contacts on a printed circuit board (12) includes etching or drilling a central opening in each copper pad (14), and then screening a mound of silver epoxy into the opening. The silver epoxy above the pad slumps to form a domed bump. The silver epoxy is then cured and is coated, in turn, by a layer of electroless nickel (24) and gold (26). The resulting gold plated contacts are of monolithic structure and function to facilitate connection to a mezzanine board.
Abstract:
A novel board for printed wiring comprising a fine conductor wiring having a clear and favorable boundary line and fabricated by an ordinal printing method such as screen printing, a printed wiring board using the same, and methods for manufacturing them. A board for printed wiring and a method for manufacturing the same are characterized in that the surface of a board is subjected to one of the surface treatments: (a) roughening, (2) plasma treatment, (3) roughening and then plasma treatment, and (4) roughening and then forming of a metal film coating by sputtering. A printed wiring board and a method for manufacturing the same is characterize in that a conductor wiring is fabricated by printing using a conductive paste containing metal particles the average particle diameter of which is 4 µm or less and the maximum particle diameter of which is 15 µm or less. Another printed wiring board and a method for manufacturing the same is characterized in that the surface of a conductor wiring fabricated using a conductive paste containing metal particles M and a binder B at a volume ratio of M/B of 1/1 to 1.9/1 is etched, a plating coating is formed on the surface.
Abstract:
The cost and complexity of an electronic pressure sensitive transducer (20) are decreased by constructing such a transducer directly on a printed circuit board (22) containing support electronics. Conductive traces (24) are formed on the printed circuit board (22) to define a contact area (26). A flexible substrate (28) having an inner surface is positioned over the contact area (26). An adhesive spacer (34), substantially surrounding the contact area (26), attaches the flexible substrate to the printed circuit board (22). At least one resistive layer (32) is deposited on the flexible substrate (28) inner surface. In use, the resistive layer (32) contacts at least two conductive traces (24) in response to pressure applied to the flexible substrate to produce an electrical signal indicative of applied pressure.
Abstract:
The disclosed invention relates to materials and processes for creating particle-enhanced bumps on electrical contact surfaces through stencil or screen printing processes. The materials are mixtures of conductive ink, conductive paste, or conductive adhesive and conductive hard particles (104). The process involves depositing the mixture (108) onto electrical contact surfaces by stencil printing, screen printing, or other dispensing techniques (110). In another embodiment, the ink, paste, or adhesive deposit. Once cured (114), the deposition provides a hard, electrical contact bump on the contact surface with a rough, conductive, sandpaper-like surface that can be easily connected to an opposing contact surface without any further surface preparation of either surface.
Abstract:
A method of testing and mounting electronic components that are to be surface-mounted. The components include on one side a plurality of contact pads that shall be connected electrically to contact pads on one side of a test board, particularly BGA components and corresponding components. The invention is characterized by applying to the component contact pads (2) a metal (5) which is liquid at room temperature or at an elevated room temperature, in a first method step; lifting the component (1) away from the surface of the metal (5) in a second method step, wherewith part (7) of the liquid metal remains on the component contact pads (2); and bringing the component contact pads (2) provided with the liquid metal into abutment with corresponding contact pads (3) on the test board (4), in a third method step.
Abstract:
A soldering process uses two or more different solder alloys. A first solder alloy (115) that undergoes a solid-to-liquid transition at a first temperature is coated (20) onto the solderable surfaces (105) of a printed circuit board (100). A solder paste (120) that undergoes this solid-to-liquid transition at a temperature greater than the first temperature is deposited on the coated solderable portions, and is heated to a temperature that is above the first temperature but below the second temperature. During this time, the first solder alloy liquifies, while the solder paste does not. The first solder alloy wets to the individual particles in the solder paste, and alloys to the solderable surfaces and the solder particles in the solder paste. The soldering composition is subsequently cooled (40) to solidify the first solder material, forming a solid and substantially planar coating on the solderable portions of the printed circuit board.
Abstract:
A method for producing an electronic circuit device includes a repair step in which, in a case where a semiconductor device once mounted on a wiring board is defective, the defective semiconductor device is removed from the wiring board and a new semiconductor device is mounted on the wiring board. The repair step includes the steps of: removing an excessive residue of a brazing metal residue remaining on lands of the wiring board from which the defective semiconductor device has been removed and leaving a uniform amount of the brazing metal residue on the lands; aligning the new semiconductor device with the wiring board; and melting the brazing metal residue which is made uniform and remains on the lands and projecting electrodes of the new semiconductor device by heating, thereby connecting the new semiconductor device to the wiring board.
Abstract:
A printed-wiring board has a copper foil (the first conductive layer) providing electric conductivity formed on one or both sides of an insulating board providing electrical insulation, an insulating layer providing electrical insulation formed at specific sites (where there are through-holes) on the first conductive layer, and a second conductive layer providing electric conductivity formed on the insulating layer. In this printed-wiring board, when the second conductive layer is formed, deposition of an electrically conductive material by plating, and polishing of the deposited electrically conductive material, these steps are repeated at least once, so that the surface of the second conductive layer can be smoothened to enhance the bonding stability of chip parts.
Abstract:
A method of connecting electrodes of a display apparatus includes a process of forming conductive metal paste on an electrode pattern on a flexible resin plate where a drive circuit device is mounted and a process of position-adjusting the electrode pattern on which the conductive metal paste is provided and the electrode pattern on a plane-type display body to heat and pressurize them. By this method, the electrode pattern on the display body and the electrode pattern on the drive circuit side are connected to each other through the conductive metal paste.
Abstract:
An improved method of forming an electrode pattern on a substrate (1) is described. The substrate is coated with a first conductive film (2a) and subjected to baking. On the first conductive film is then overlied a second conductive film (2) which mends possible fissures of the first conductive film which, besides, would produce open circuits in the pattern.