Abstract:
A wire-bonding machine includes a heat block for supporting a lead frame during wire-bonding. A clamp mechanism in the machine clamps leads of the lead frame during wire-bonding by fixedly holding sets of the leads against the heat block one set at a time. A wire-bonding tool wire-bonds leads clamped by the clamp mechanism to bond pads on an integrated circuit die. By clamping leads of the lead frame in separate sets, the machine provides improved clamping for lead frames with leads requiring clamping in different planes.
Abstract:
A method for manufacturing raised contacts on the surface of an electronic component includes bonding one end of a wire to an area, such as a terminal, of the electronic component, and shaping the wire into a wire stem configuration (including straight, bent two-dimensionally, bent three-dimensionally). A coating, having one or more layers, is deposited on the wire stem to (i) impart resilient mechanical characteristics to the shaped wire stem and (ii) more securely attach ("anchor") the wire stem to the terminal. Gold is one of several materials described that may be selected for the wire stem. A variety of materials for the coating, and their mechanical properties, are described. The wire stems may be shaped as loops, for example originating and terminating on the same terminal of the electronic component, and overcoated with solder. The use of a barrier layer to prevent unwanted reactions between the wire stem and its environment (e.g., with a solder overcoat) is described. Bonding a second end of the wire to a sacrificial member, then removing the sacrificial member, is described. A plurality of wire stems may be formed on the surface of the electronic component, from different levels thereon, and may be severed so that their tips are coplanar with one another. Many wire stems can be mounted, for example in an array pattern, to one or to both sides of electronic components including semiconductor dies and wafers, plastic and ceramic semiconductor packages, and the like.
Abstract:
An apparatus and method of forming improved wire bonds between the contact pads on semiconductor devices and individual lead frame fingers of a lead frame. The apparatus and method includes the use of a penetrating individual independent lead finger clamp during the wire bonding process to provide increased stability of the individual lead finger for improved bonding by the clamp penetrating a portion of the lead finger being bonded. If desired, the apparatus and method also provides for the use of either a penetrating or non-penetrating fixed clamp for the lead fingers during the wire bonding process in addition to the penetrating individual independent lead finger clamp during the wire bonding process to provide increased stability of the individual lead finger for improved bonding. The apparatus and method contemplates the replacement of the penetrating fixed clamp with another, or second, penetrating independent clamp in addition to the first individual independent lead finger clamp during the wire bonding process.
Abstract:
Screen printing and chip mounting are executed in a dry air atmosphere to prevent generation of solder balls due to absorption of moisture by a flux ingredient of paste solder. Screen printing of the solder on a board takes place in a space which has the board, a printing screen and a squeegee arranged therein and is formed therein with a dry air atmosphere having a pressure slightly higher than that of an atmosphere outside the space. Likewise, mounting of a chip on the board is carried out in a like space. Also, a reflow step is executed in a reflow oven kept at a dry air atmosphere.
Abstract:
Disclosed is a solder injection mold apparatus and method for providing solder balls to a printed circuit board substrate using the solder injection mold apparatus in the plastic ball grid array (PBGA). The solder mold through holes are chamfered at entry and at exit ends to assist in receipt of molten solder and the formation and transfer of solder balls to lands on the substrate. A blind recess is provided in the second major surface of the mold, i.e. the side facing the substrate, in order to accommodate electronic components mounted thereon. Solder balls are delivered and metallurgically affixed to the lands in a process that requires only one reflow, leaving the through holes clean of solder and the mold ready for reuse. The material of which the substrate, mold and base plate are comprised is selected to be non-wettable by solder and mutually compatible with respect to CTE when exposed to temperatures of molten solder.
Abstract:
The invention relates to a method of connecting components (12) to at least one carrier (11), for example by soldering or gluing. Such a method is carried out in an oven (1) through which carriers are moved. Preferably, the carrier is a flexible foil. The carrier separates the oven into an upper part (2) and a lower part (3). In both parts a hot air stream (14) is created and directed toward the carrier. Owing to the separation by the foil the hot air stream in the upper part cannot reach the lower part and vice versa. The temperature of the hot air stream in the upper part differs from that (is, for example, higher than) in the lower part. The heating elements in the upper part of the oven may all have the same high temperature (for example, 240.degree. C.) and the heating elements in the lower part may all have the same low temperature (for example, 60.degree. C.). By adjusting at least one air stream the desired temperature at the location of the carriers (for example, at solder lands 17) can be obtained very rapidly (comparable with a hot/cold water mixing tap).
Abstract:
High density packaging of semiconductor devices on an interconnection substrate is achieved by stacking bare semiconductor devices 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 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, 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. 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 are mounted directly to bond pads on semiconductor dies, prior to the dies being singulated (separated) from a semiconductor wafer. This enables the semiconductor dies to be exercised (e.g., tested and/or burned-in) by connecting to the semiconductor dies with a circuit board or the like having a plurality of terminals disposed on a surface thereof. Subsequently, the semiconductor dies may be singulated from the semiconductor wafer, whereupon the same resilient contact structures 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 of the present invention as the resilient contact structures, burn-in can be performed at temperatures of at least 150.degree. C., and can be completed in less than 60 minutes.
Abstract:
An electronic element producing apparatus comprises a bonding tool 1 which has a first supply hole 2 for passing a bonding wire 3 used to bond a bonding pad 6 of a semiconductor device 5 and an external conductor which is to be connected electrically with the bonding pad 6, and contacts a leading end 3b of the bonding wire 3 protruded outside from the first supply hole 2 to the bonding pad 6, and which also has a second supply hole 12 to supply a bonding material to bond the bonding pad 6 and the leading end 3b of the bonding wire 3, the second supply hole 12 being formed to supply the conductive material to a contact point between the bonding wire 3 and the bonding pad 6. Therefore, the bonding pad 6 and the bonding wire 3 can be bonded without applying a dynamic or thermal load to the semiconductor device 5.
Abstract:
A fixture for use in the bonding of a plurality of chips each to a respective one of a plurality of substrates includes a lower vacuum chuck and a frame member supported on the chuck for reciprocatory motion toward and away from the chuck surface. The chuck surface is arranged to hold substrates with predeposited solder in pockets at predetermined locations thereon. The frame member has openings aligned with those pockets and weights which extend through the openings. After substrates are placed on the chuck surface, the substrates are heated so that the predeposited solder reaches eutectic status, and then chips are placed on the substrates. The frame member is then mounted on the chuck and gradually lowered until the weights press against respective chips, thereby holding the chips in position on the substrates. The entire assembly is then transported to a solder reflow bonding station.