Western Electric Company, Inc.

At&t Technologies, Inc.

Jack J Monahan

Fred J Schneider

Raymond H Booth

David P Ludwig

Joseph N Lesyk

Norman Bahnck

John A Boyer

Alan R Becker

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

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

An article (11) which has a body portion (12) and lateral protrusions (14) at fixed angular positions is oriented and centered with respect to predetermined axes. Sloped walls (61) of a plurality of channels (62) located about a central axis (24) engage lateral edges of the protrusions to urge the protrusions laterally toward desirable positions in relationship to the axes. The disclosed methods and apparatus are advantageously applied to a four-leaded electronic chip as a typical example of the article with respect to which orienting and centering offers desirable precision for handling such article during packaging operations.

Apparatus for and methods of orienting and centering an article having

Compliant bonding of successive beam-lead semiconductor devices to successive metallic patterns on substrates is accomplished with a bonding apparatus that uses an indexable compliant member. A bonding head of the apparatus is provided with a single movable tip which disengages from the compliant member during indexing of the member. The movable tip engages with a portion of the compliant member that is suspended between two drive sprockets when it is desired to perform a bonding operation. The engagement of the tip with the compliant member produces tension in the member. The tension results in a precise and flat configuration within the engaged portion of the member. The flat configuration enhances accurate alignment of workpieces to the compliant member. A toggle linkage is described as a desirable system for moving the bonding tip with respect to the head.

Compliant bonding method

A bonder for attaching in succession small articles such as electronic devices to substrates has eight stations located along the path of a rotary member. The rotary member supports eight holders for substrates which are moved in sequence from station to station. At a first station a substrate is loaded onto one of the holders. The holder is then moved to an alignment station and transferred from the support member to a planar manipulator. An optical alignment control system recognizes a position of the substrate on the holder and controls the manipulation of the holder to align a substrate to a predetermined reference axis. The holder is then transferred back to the support member to fix the position of the substrate with respect to the support member. At the next station an article is also aligned to a corresponding reference axis and then tack-bonded or preliminarily attached to a bond site on the substrate. The article is then permanently bonded and the substrate with the bonded article is unloaded at an unload station. Prior to the completion of the cycle, the substrate holder is recentered to a starting position to prevent cumulative movement of the substrate holder with respect to the support member.

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Allentown, PA, United States of America

Jack J Monahan