Western Electric Company, Inc.

At&t Technologies, Inc.

Fred J Schneider

Raymond H Booth

Jack J Monahan

Philip William Seitzer

George F Wilkinson, Jr

Daniel J Roman

Joel R Bitler

Michael W Bodnar

George A Chayka

Alan R Becker

Bennett L Koppenhaver

Ronald D Kauffman

In methods of and apparatus (28) for indexing a repetitively patterned strip (12) past a plurality of work stations, such as, for example, a bonding station (33) and a dewebbing station (65) of a lead frame bonder, a cyclical, automated adjustment of the strip (12) with respect to the bonding station (33) eliminates repeated meticulous manual fine adjustments of the strip. An adjustment of the position of the strip (12) is achieved by adjusting the positions of travel limit stops (109 and 111) of an incremental feed mechanism (46). Simultaneously with the adjustment of the travel limit stops (109 and 111), an adjustment is made in the same magnitude and in the same direction as the adjustment to the limit stops in the position of the dewebbing station (65). Similar adjustments may be made to any other station, an accurate position of which with respect to the position of the strip (12) is desirable.

Methods of and apparatus for indexing a repetitively patterned strip

A hybrid integrated circuit package (11) typically includes a circuit substrate or article (12) on which are formed thin film components (17, 18, 19) of a circuit (22) and to which is bonded at least one semiconductor chip (21). Prior to bonding the chip (21) to the article (12) the circuit (22) undergoes various tests and adjustment operations. An electric element, preferably a resistance element (36), is formed on the article (12). The element (36) is functionally independent of the circuit (22) on the article (12). A first, initial value of the element (36) marks the article (12) as belonging to a first group of articles having first circuit characteristics. The initial value of the element (36) is selectively altered to a second value upon a determination that the article (12) has circuit characteristics other than those of the first group. In the described preferred embodiment the first group is a group of electrically acceptable articles (12), while other characteristics are those of defective articles. The mark is typically altered by a current of sufficient magnitude to burn portions of the element (36), or by selective application of radiant energy such as a laser beam (83). Identifying the altered mark permits articles (12) having defective circuits thereon to be selectively eliminated from further processing steps.

Methods of marking and electrically identifying an article

Articles (18) are transferred from a first position, such as a feed track (37) on which they are located closely spaced, to a second position such as a heat seal apparatus. At the heat seal apparatus the spacing of the articles is to coincide with the spacing of frame members (32) to which the articles are to be joined. The change in the spacing occurs during the transfer of the articles from the first to the second positions by means of a transfer mechanism (41). A plurality of pickup members (43) are slideably mounted to an arm (44) of the mechanism (41). The pickup members (42) which are resiliently urged apart with respect to each other are forced together at one end of the travel of the arm (44) to assume the close spacing established by the width of the pickup members. At the other end of the travel of the arm (44) the resilient urging force drives the pickup members (43) against predetermined stop positions.

Methods of and apparatus for transferring articles

Articles (12) are loaded onto a movable article holder such as pedestals (18) mounted to a rotary table (20). The table is indexed to advance the articles (12) first to a centering station (41) and then to a work station (49) which may be, for example, a lead frame bonder. At the centering station (41) a typical centering mechanism (22) urges the articles to a predetermined center location. While the centering mechanism may be adjusted to and fixedly located in a position to center the articles (12) to a theoretical center removed by precisely one step or a multiple thereof from the bonding position, the centering station (41) provides for tangentially shifting the theoretical center with respect to the table (20). Any shift of said theoretical center is made to offset an anticipated error of alignment of the articles, even though such error may be unique to each of the pedestal positions.

Centering articles

A Hybrid Integrated Circuit package (11) typically includes a circuit substrate or article (12) on which are formed thin film components (17, 18, 19) of a circuit (22) and to which is bonded at least one semiconductor chip (21). Prior to bonding the chip (21) to the article (12) the circuit (22) undergoes various tests and adjustment operations. An electric element, preferably a resistance element (36), is formed on the article (12). The element (36) is functionally independent of the circuit (22) on the article (12). A first, initial value of the element (36) marks the article (12) as belonging to a first group of articles having first circuit characteristics. The initial value of the element (36) is selectively altered to a second value upon a determination that the article (12) has circuit characteristics other than those of the first group. In the described preferred embodiment the first group is a group of electrically acceptable articles (12), while other characteristics are those of defective articles. The mark is typically altered by a current of sufficient magnitude to burn portions of the element (36), or by selective application of radiant energy such as a laser beam (83). Identifying the altered mark permits articles (12) having defective circuits thereon to be selectively eliminated from further processing steps.

Article carrying a distinctive mark

A thermode (12) of a thermocompression bonding head (11) is adjustably mounted to a frame (35). A bonding tip (26) of the thermode (12) rests against a reference surface (17). After an initial adjustment of the thermode (12) with respect to a bonding platform (37), the bonding tip (26) may be removed from the thermode (12) and replaced by another identical tip (26) without a need for readjusting the thermode (12) with respect to the bonding platform (37). A comparatively large interface surface area between a dovetailed groove (16) and the mating surfaces of the bonding tip (26) and a wedging action of the dovetailed section urging mating surfaces against each other minimize thermal resistance across the interface between the thermode (12) and the bonding tip (26).

Bonding head

In making electronic components, it is often necessary to bond a lead frame to an insulating substrate. In carrying out the bonding, it is desirable to provide compensation to prevent cracking of the substrate. At the same time it is also desirable to prevent relative motion between the substrate and lateral guides for accurately positioning the substrate with respect to a bonding tip. The prevention of such motion reduces the likelihood of damage to the guides. To these ends, the substrate is positioned on a supporting pedestal and on the first ends of a plurality of elongated members or rods slidable through the pedestal and having second ends mounted to spring elements. In so positioning the substrate, it is located between lateral guides which are fixed to the pedestal. Prior to bonding, the surface of the pedestal is urged flush with the surfaces of the first ends of the rods. Then, during bonding the pedestal is moved with the guides and the substrate. Also, during bonding the surfaces of the first ends of the rods slide through the pedestal to permit the spring elements to compensate for irregularities in the substrate to reduce stresses introduced into the substrate to reduce the cracking thereof.

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Northampton, PA, United States of America

Fred J Schneider