Abstract:
An automated discreet soldering system for plated holes of a printed wiring board, having a free piston type crucible mode of graphitic material, which is propelled along a guided path by pressurized nitrogen. A laser beam is directed along a path substantially coincident with the path of travel of the crucible to heat a susceptor surface for melting the solder therein.
Abstract:
First and second transparent metallized gauge plates (52 and 52') of solder-nonwettable, heat-resistant material, such as glass or quartz, each have a solder wave test pattern in the form of spaced parallel metal strips (56 and 56') formed thereon. The metal strips (56) on the first gauge plate (52) are of progressively increasing widths, with a narrowest strip located adjacent one edge of the plate and a widest strip located adjacent an opposite edge of the plate. The metal strips 56' on the second gauge plate (52') are of uniform widths. The first gauge plate (52) is engaged with a solder wave (34) to measure the activation level of a soldering flux (44) being introduced into the solder wave, and thereby to determine the capability of the solder wave to produce properly soldered printed circuit board assemblies (10). The second gauge plate is engaged with the solder wave (34) to measure and/or adjust other flow characteristics of the solder wave, such as a width of solder wave impingement (80 ) on the printed circuit board assemblies (10).
Abstract:
A method for selective removal of metallization in integrated circuits. A uniform metal film is applied over a patterned resist layer. A short pulse of radiant energy is then applied to the whole surface of the metal film. The resist underneath the metal film is locally heated enough to cause outgassing, which breaks the mechanical bond between the metal film and the resist. The metal film over the patterned resist layer is then removed, leaving the deposited metal film in place over areas which were not covered by the resist film.
Abstract:
A continuous vapor processing system for vapor phase soldering, degreasing, or similar processes wherein a product is moved into and out of a vessel in a continuous manner via open conduits or channels while preventing escape of vapor from the processing tank and the conduits.
Abstract:
A via (21) is formed in a multilayer printed circuit board (10) by initially etching apertures (14) in the land areas (13) of the circuit pattern on the layers (11) prior to uniting the layers. A beam (16) of laser energy is then directed through the apertures to form a via through the printed circuit board. Each via is defined by the apertures in a plurality of vertically aligned land areas. The via is then electrolessly plated to provide electrical connections between vertically aligned land areas.
Abstract:
In the wave soldering of terminals of an electrical device, such as a miniaturized printed circuit board assembly, the board is moved along a predetermined path so that it initially engages a first solder wave flowing counter to the direction of the board movement and subsequently engages a second solder wave flowing in the direction of board movement. The velocity of the solder in each of the solder waves is controlled independently by having separate independent pumping systems. Thus, the solder waves can be set at different independent velocities to achieve proper soldering of the terminals and associated conductor paths while reducing crossovers or bridges (i.e., shorts) between the terminals and the conductor paths as a result of the close spacing thereof.
Abstract:
A process is provided for improving the solderability of electric circuit boards with conductor paths composed of copper or copper alloys, in which, at least at the locations to be soldered, the conductor paths are cleansed in a first solution and are thereby deoxidized, and are then activated in a second solution.
Abstract:
A printed wiring board is oriented with a wiring surface facing up for mass soldering. Molten solder is pumped from a tank onto a trough and flows in a thin, wide stream across the upper surface of the printed wiring board which is held down to prevent the board from floating on top of the solder.
Abstract:
A mass soldering system is described in which a standing wave of molten solder is formed. The solder wave is characterized by having a substantially horizontal crest, and the wave has varying pressures along its flow path. In a preferred embodiment of the invention the wave pressures are varied to produce a wave having increasing pressure along its flow path whereby a substantially uni-directional wave may be formed which is highest adjacent its rear.
Abstract:
A mass wave soldering system is described in which a standing wave of molten solder is formed from a static head of solder. The system comprises a soldering apparatus which has a two-compartment solder reservoir. The first compartment is designed to hold a first portion of the solder supply at a first liquid level with a layer of oil floating on the solder therein. The second compartment is designed for holding a second portion of the solder supply at a second liquid level above the first liquid level with a layer of oil floating on the solder therein. A sump and nozzle are positioned in the first compartment so that the sump is partially submerged in the molten solder therein, with the nozzle above the solder and oil levels therein, but below the solder and oil levels in the second compartment. The apparatus also includes a first conduit having an inlet disposed in the second compartment and an outlet disposed in the sump for carrying a flow of molten solder between the second compartment and the sump, and a second conduit having an inlet disposed in the second compartment for carrying a flow of oil from the second compartment and for depositing the oil onto the solder overflow adjacent the nozzle. Completing the apparatus are a conduit and pump for transferring molten solder and oil from the first compartment into the second compartment so as to maintain the liquid level of solder and the oil in the second compartment.