Abstract:
An electrical component includes a conductive substrate (18), a tin layer (19) formed on the substrate, and a coating (22) of a foam formed on the tin layer to impede tin whisker growth, the coating comprising a foam (28) having voids (30) dispersed therethrough. A method for impeding tin whisker growth from a tin plating or finish formed over an electrical component includes covering the tin plating or finish with a coating of intumescent paint, and thereafter expanding the intumescent paint into a foam having voids dispersed therethrough.
Abstract:
Eine Schmelzsicherung für Leiterplattenmontage besitzt Anschlüsse, die mit Leiterbahnen auf der Leiterplatte elektrisch verbindbar sind, sowie mindestens eine leitfähige und schmelzbare Verbindung zwischen den Anschlüssen. Sie ist so gestaltet, dass sie kostengünstig einstückig aus Blech oder leitfähigem Kunststoff gefertigt werden kann. Die Schmelzsicherung kann eine Überhitzung einer Heizvorrichtung, in der sie eingesetzt wird, verhindern, indem sie angepasst ist, die mindestens eine leitfähige und schmelzbare Verbindung bei thermischer Überlast zu trennen.
Abstract:
A method for reducing whisker formation and preserving solderability in tin coatings over metal features of electronic components. The tin coating has internal tensile stress and is between about 0.5 m and about 4.0 m in thickness. There is a nickel-based layer under the tin coating.
Abstract:
High density packaging of semiconductor devices on an interconnection substrate is achieved by stacking bare semiconductor devices (402, 404, 406, 408) atop one another so that an edge portion of a semiconductor device extends beyond the semiconductor device that it is stacked atop. Elongate interconnection elements (422, 424, 426, 428) extend from the bottommost one of the semiconductor devices, and from the exposed edge portions of the semiconductor devices stacked atop the bottommost semiconductor device. Free-ends of the elongate interconnection elements make electrical contact with terminals of an interconnection substrate (430), such as a PCB. The elongate interconnection elements extending from each of the semiconductor devices are sized so as to reach the terminals of the PCB, which may be plated through holes (432, 434, 436, 438). The elongate interconnection elements are suitably resilient contact structures, and may be composite interconnection elements comprising a relatively soft core (e.g., a gold wire) and a relatively hard overcoat (e.g., a nickel plating).
Abstract:
Resilient contact structures (430) are mounted directly to bond pads (410) on semiconductor dies (402a, 402b), prior to the dies (402a, 402b) being singulated (separated) from a semiconductor wafer. This enables the semiconductor dies (402a, 402b) to be exercised (e.g., tested and/or burned-in) by connecting to the semiconductor dies (702, 704) with a circuit board (710) or the like having a plurality of terminals (712) disposed on a surface thereof. Subsequently, the semiconductor dies (402a, 402b) may be singulated from the semiconductor wafer, whereupon the same resilient contact structures (430) can be used to effect interconnections between the semiconductor dies and other electronic components (such as wiring substrates, semiconductor packages, etc.). Using the all-metallic composite interconnection elements (430) of the present invention as the resilient contact structures, burn-in (792) can be performed at temperatures of at least 150 DEG C, and can be completed in less than 60 minutes.
Abstract:
An improved connector (10) for an electronic module (16) or the like includes a housing (22, 24) having a socket opening that is sized and configured to accept an electronic module, and a plurality of terminals mounted to the housing. Each of the terminals (26) has a foot portion (28) having a layer of non-solderable material coated on one side of the foot portion to prevent solder from adhering to that side. A capillary nest (54) is formed by a channel surface on the underside of the foot portion when the terminal is mounted on a conductor pad such that solder flows through the capillary nest under the influence of capillary forces from the side of the terminal having a non-solderable coating thereon to the other side for forming a solder joint on that other side. A ring (50) of non-solderable material is coated around a middle portion of the terminal to prevent solder from flowing to the electrical contact surfaces located above the ring. As a result, the connector terminals can be soldered to a printed circuit board or the like in a simple and inexpensive manner and without the formation of known solder defects.
Abstract:
There is disclosed a process for the assembly of an electronic package (30) in which the outer lead ends (14) of a leadframe (50) are solderable (38) to external circuitry (36) without the necessity of a tin or solder coat. An oxidation resistant layer (44) is deposited on the leadframe (50) prior to package (30) assembly. The oxidation resistant layer (44) is removed prior to outer lead (14) soldering (38) providing a clean, oxide free metallic surface (46) for soldering (38).
Abstract:
A method and apparatus for interconnecting electronic circuits using nearly pure soft annealed gold mechanically compressed within through-plated holes. The invention has its application in attaching integrated circuit dice (104) directly to circuit boards (110) by ball bonding gold wires (101) to the bonding pads of the integrated circuit dice in a substantially perpendicular relationship to the surfaces of the dice and inserting the gold leads into through-plated holes (111) of circuit boards (110) which provide an electrical and a mechanical connection once the leads are compressed within the through-plated holes. The present invention also finds its application in the interconnection of sandwiched circuit board assemblies where soft gold lead wires are inserted into axially aligned through-plated holes of the circuit boards and compressed so that the gold lead wires compress and buckle within the through-plated holes, forming an electrical connection between the circuit boards.
Abstract:
An electronic component includes: an electronic component body; and a lead secured to the electric component and including a projection portion defined by first and second inclined portions facing each other. The solder wettability of the first inclined portion is smaller than the solder wettability of the second inclined portion.