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Precision Chip Positioning by Footprint

IP.com Disclosure Number: IPCOM000046584D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Arnold, OE: AUTHOR [+2]

Abstract

Positioning a chip by using the chip's footprint (solder ball pattern), rather than the present technique of locating using an edge of the chip, provides a much more precise method for chip placement. The accuracy is maintained from lot to lot with no adjustments necessary due to irregularities in the dicing of the chips. The chip-locating device, shown in Figs. 1a and 1b, consists of the precision nest 1, which in most cases uses a V-groove pattern 8 to locate the chip 6 by means of the solder balls 7. The chip 6 is transported in the nest 1 by means of a built-in air track. The chips 6 enter the air track and the nest 1 one at a time from a chip storage device, such as a helix or linear track.

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Precision Chip Positioning by Footprint

Positioning a chip by using the chip's footprint (solder ball pattern), rather than the present technique of locating using an edge of the chip, provides a much more precise method for chip placement. The accuracy is maintained from lot to lot with no adjustments necessary due to irregularities in the dicing of the chips. The chip-locating device, shown in Figs. 1a and 1b, consists of the precision nest 1, which in most cases uses a V-groove pattern 8 to locate the chip 6 by means of the solder balls 7. The chip 6 is transported in the nest 1 by means of a built- in air track. The chips 6 enter the air track and the nest 1 one at a time from a chip storage device, such as a helix or linear track. As the chip 6 comes against the end stop 9, guided by the side rails 10, the chip solder balls 7 are no more than one half the ball width out of position relative to the V-groove locator 8. The air track float and directional thrust moves the chip into position above the V- groove pattern 8 and holds it against the stop 9 until it is pulled down into the precision location of the V-groove nest. The chip 6 is pulled down by a vacuum port 5 so that the solder balls 7 are seated in the V-groove pattern 8. The precision nest 1 is mounted into the track fixture 2 where it is held and adjusted using the gauge plate 3. The master pin 4 is held in the pickup probe. The track fixture 2 is moved until the master pin 4 freely enters the hole...