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Probe Positioning Algorithm for Testing Multi-Chip Flex-Tapes

IP.com Disclosure Number: IPCOM000101977D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 84K

Publishing Venue

IBM

Related People

Snyder, SC: AUTHOR

Abstract

A testing algorithm to solve mechanical probing problems for automated tests. This method allows an automated system to make contact with small pads or solderballs with mechanical probes reliably and quickly. Traditional probing approach would give poor test yields due to misalignment. This adaptive probing algorithm allows faster test cycles, higher yields, and less mechanical fixturing sensitivity.

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Probe Positioning Algorithm for Testing Multi-Chip Flex-Tapes

       A testing algorithm to solve mechanical probing problems
for automated tests.  This method allows an automated system to make
contact with small pads or solderballs with mechanical probes
reliably and quickly.  Traditional probing approach would give poor
test yields due to misalignment.  This adaptive probing algorithm
allows faster test cycles, higher yields, and less mechanical
fixturing sensitivity.

      It is assumed that the majority of multi-chip flex-tape
assemblies are made within tolerance so that an initial probe of the
solderballs or pads will make good contact with each of the probes.
However, not all probes may contact every solderball which would
ordinarily require a manual adjustment to achieve 100 percent contact
for any single chip.  A 3x3 grid in the X-Y plane was set up as
the search area for positioning of probes.  (See Fig. 1.)

      Grid of Probing Positions in the X-Y Plane.  Probing would
start in position 0 and move to a greater position number as needed.
The prober returns to the origin when multi-chip substrate testing is
finished.

      There may not be a set of coordinates that would allow all
probes to contact all solderballs, however, one may find a set of
coordinates that would suffice for testing one or two of the chips
and another set of coordinates to test the remaining chips.  The
solderballs are grouped so that one chip's solderballs are in...