At&t Technologies, Inc.

Western Electric Company, Inc.

American Telephone and Telegraph, Co.

Michael K Avedissian

Donald M Large

Joseph A Tamashasky

Earl D Hertzog

Anthony J Schorr

A head (158) precisely registers an article (10) to a site for operations such as bonding. The article (10) may be an electronic chip (10) containing a plurality of sides (12-15) having top edges for engaging the head (158) and bottom edges for registering to a topside (95) of a pedestal (20). A body (161) has an upper portion adapted for support and a lower portion terminating in a downwardly presented, working face (159). Face 159 includes a cavity (166) formed by walls (167-170) having inwardly and upwardly directed surfaces (171-174) for engaging corresponding top edges of the chip (10). The chip (10) is at least partially disposed within the cavity (166) making it difficult for an operator to see, especially when a fixed microscope is required for viewing. A bore (175) communicates with the cavity (166) and may be connected to a vacuum source for drawing a chip (10) into the cavity and for removably engaging the same to the engaging surfaces (171-174). Preferably, the front wall (168), facing the operator, has recessed end portions (100 and 102). Such recesses (100 and 102) reveal, preferbly extending to corners, bottom edges of the engaged chip (10) sufficient for registering such edges and the chip (10) to the topside (95) of the pedestal (20).

Registering articles to sites with recessed ultrasonic bonding tool head

A head (45) engages a chip (10) having peripheral sides (16), and then engages the chip (10), to a workpiece (35) for bonding chip (10) to a substrate (30). Body (46) has a lower portion terminating in a downwardly presented, working face (48). For receiving chip (10), face (48) has a cavity (54) formed by a plurality of inwardly and upwardly directed surfaces (56). Such surfaces (56) engage upper edges of, and position a chip (10) such that at least a portion of the peripheral sides (16) protrude from working face (48). Body (46) includes a vacuum bore (58) adapted for connection between face (48) and a vacuum for removably engaging and holding chip (10) against surfaces (56). Pockets (60) are also provided in face (48) and connected to a vacuum for moving air streams toward face (48) at the sides (16) of an engaged chip ( 10). Such streams are sufficient in force, direction and distribution around the sides (16) that when an engaged chip (10) is moved adjacent to a free workpiece (35), the air streams capture portions (38) and hold workpiece (35) against chip (10). The chip (10) and the workpiece (35) may be simultaneously registered to a site (32) on a heated substrate (30). Then workpiece (35) becomes liquefied and is uniformly applied and reacted to contact surfaces for the bonding. The pockets (60) may be directly supplied by the same vacuum for engaging chip (10) or to a different vacuum. Alternatively, the pockets (60) may open into cavity (54) such that a vacuum sufficient to engage chip (10) and then the workpiece (35).

Engaging second articles to engaged first articles

Articles such as miniature laser chips (15) are individually removed from an array on an adhesive web (20). A subjacent forming die has a planar, central surface (160) containing a vacuum cavity (120) and peripheral sloping surfaces (162). The web (20) has an adhesive side for holding the chips (15) and a smooth side for conforming to surfaces (160) and (162) of die (116). A leading target chip (15) is located centrally of cavity (120) on a planar portion of web (20) which portion is substantially restrained from movement away from die (116) by vacuum drawn in cavity (120). At the smooth side of web (20), within cavity (120), there is a needle (135) which is movable perpendicularly of and through web (20) along a path containing the target chip (15). At the adhesive side of web (20), opposite needle (135), there is a pickup probe (147) having a vacuum port (166 ) to retain a chip (15). Also, probe (147) is movable relative to and with a target chip (15) and the needle (135). Conveniently, probe (147) is registered with and forces a chip (15) into web (20) to reflect light and confirm contact. Then subjacent needle (135) is advanced to contact the same chip (15) from the smooth side of web (20). In synchronization, the probe (147) and needle (135) are then moved, with the chip (15) held therebetween, at least until the chip (15) is separated from web (20).

Removing articles from an adhesive web

In using a gas torch it is often necessary to maintain a uniform flame. This can be accomplished by maintaining a constant pressure at the torch tip. A pressure transducer is placed at the output of a generator that produces gas by electrolysis for the torch. The transducer indicates changes in the gas pressure by changing resistance. The transducer is coupled to a resistance-capacitance circuit and forms a variable part of the resistance of the circuit. This circuit, in turn, is coupled to the firing gate of a triac which controls the rate of gas disassociation of the electrolytic solution in the gas generator by varying the amount of current fed to the gas generator. When the pressure at the output of the generator varies, the resistance of the pressure transducer changes thereby changing the RC time constant of the resistance-capacitance circuit. Such a change modifies the firing rate of the triac and, therefore, the rate of gas generation and pressure.

Growing community of inventors

Mohnton, PA, United States of America

Michael K Avedissian