Abstract:
In a method for welding a lead wire or bonding wire from a microcircuit chip mounted on a lead frame to a lead frame finger, the lead frame finger is preheated prior to any substantial electrical or thermal coupling between the lead frame finger and chip. Intense but controlled energy is applied to the lead frame finger at levels which might otherwise damage the IC chip. In one embodiment the lead frame finger is preheated to a temperature below the melting point of the metal comprising the lead frame. Enhanced bonding is thereafter effected by thermocompression bonding etc. In another embodiment the preheating step comprises melting a portion of the surface of the lead frame finger, forming a molten pool or puddle in the surface. Bonding of the lead wire is effected by immersing a section of the wire in the molten pool or puddle. In order to preheat the lead frame finger a controlled pulse train is delivered for arc discharge at the bonding location. Bonding apparatus and circuitry for preforming the method are described.
Abstract:
Method and apparatus for forming a ball at the end of bonding wire or lead wire in a capillary wire holding and bonding tool is described suitable for ball bonding of copper and aluminum lead wire to integrated circuit chips. A ball is formed by substantially enclosing the end of the bonding wire in a shroud or shield, flooding the shroud or shield and the end of the bonding wire with an inert gas, and generating a controlled pulse train of a preset count of electrical pulses for establishing arc discharge between the wire and the shroud or shield. The method permits precise control and metering of energy delivered by controlling the parameters of the pulses of the pulse train for melting and forming a ball of uniform quality without oxidation of the metal. Corresponding apparatus and circuitry are described which may be retrofitted into stock ball bonding machines or provide new machines.
Abstract:
An electrically conductive connection is disclosed for the active parts of an electrical component or of an integrated circuit to terminals for external connection. The connection consists of a very thin gold wire and of a metal layer which are situated on the electrical component or on the integrated circuit. The gold wire is connected to the metal layer by means of thermocompression. The metal layer is provided with perforation holes at least in the area of the nailhead of the gold wire formed due to thermocompression, the perforation holes being provided to improve the contact.
Abstract:
A solderless capillary chip formed of a corundum-system precious stone such as ruby or sapphire, for use in electrical windings and the like. The inner bore of the chip is enlarged adjacent the exit end thereof, to permit relaxation of the wire to be pressure-bonded and thereby provide an improved contact situation for the next pressure-bonding operation.
Abstract:
Method for welding fine wires to connecting terminations born by the base of a semiconductor device, using a tool for welding and cutting the wire in the form of a tube (9) which acts by its end face (11) containing the wire (12) to be welded, of which the outer strand (13) is to be welded to the termination (6), an incipient rupture (16) being formed by the inner angle (17) of the tube, and a limited flattening (H) being obtained by contact (40) between part of the end face of the tube and the termination, the value (H) being determined by the choice of an angle (P) created between the termination (6) and the end face (11) of the tube.
Abstract:
A contacting device for making a wire connection on a microcircuit by applying ultrasonics or thermocompression. A contacting horn is provided with a capillary which, in turn, is associated with a wire clamping device for feeding or clamping the wire during movement of the contacting horn. The wire clamping device has two clamping members for grasping the wire. The clamping members are movable relative to each other for clamping the wire, and both are arranged to pivot jointly to move the clamped wire in its lengthwise direction. A controllable actuation unit is each associated with the second clamping member which moves relative to the first, and the two clamping members jointly. The clamping members may be formed as a strip for grasping the wire between outer end regions. The second clamping member is mounted on a support of the first clamping member, and its outer end is pressed by a leaf spring fastened to the first clamping member.
Abstract:
A contacting head for making a wire connection, particularly an aluminum or gold wire connection on an integrated circuit by ultrasonic or thermocompression bonding, in which a contacting arm is provided with a concave contacting tool or a capillary, and supplies ultrasonic or heat energy. The concave contacting tool has a gripper, or the capillary has a wire clamping device for effecting a feed or clamping of the wire during movement of the contacting arm. A driving unit provides for threading the wire through a wire guiding device which is entirely enclosed, and through the concave contacting tool or the capillary. The driving unit also provides for controlling the wire tension and produces a gas stream in the enclosed wire guiding device. A magnetic arrangement with a permanent magnet and a non-ferrous core provides for electrodynamic contact pressure control of the contacting arm and for control of the gripper. The wire supply spool is encapsulated and mounted on a base, together with a housing which is vertically movable on the base and mounts the contacting arm, the driving unit and the gripper or wire clamping device. The wire guiding device connects the wire supply spool to the driving unit, and is in the form of an elastic metal tube for the wire.
Abstract:
A method for the electrodeposition of osmium, ruthenium or their alloys from alkali metal salts of the same in a nonaqueous solvent capable of permitting dissociation of the salt and having low surface tension (e.g., methanol or dimethyl formamide) or mixtures. A silicone layer chemically bonded to the surface of said electrodeposited layer. Also, a bonding tool having a tip coated by either of the above electrodeposited layer or the silicone layer, or both.
Abstract:
An integrated circuit assembly which includes a ceramic substrate for thick film power circuits having a cermet circuit pattern and semiconductor dies on one generally flat face and a convector surface configuration on the opposite face.
Abstract:
A bonding tool and method is disclosed for bonding the ends of a threadlike wire lead to two spaced-apart regions of a semiconductive device or other electronic article. One form of this invention includes a bonding tool having a tip for use with a reel of lead wire. The tip has an outwardly extending tapered groove on its working surface for producing an elongated wedgeshaped bond with the thinnest section of the wedge at the end of the bond adjacent to the reel. The unbonded wire adjacent the thinnest wedge section, extending from the source reel, is readily detached from the bonded portion with a light tug.