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Positioning Fixture for Ic Chip Testing Board

IP.com Disclosure Number: IPCOM000101481D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Apruzzese, G: AUTHOR [+2]

Abstract

The probing system necessary for wafer parametric testing in a production line includes a ring-shaped piece of printed circuit, interfacing cables connected to test apparatus on one end, and the micrometric tips actually in contact with the wafer surface on the other end.

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Positioning Fixture for Ic Chip Testing Board

       The probing system necessary for wafer parametric testing
in a production line includes a ring-shaped piece of printed circuit,
interfacing cables connected to test apparatus on one end, and the
micrometric tips actually in contact with the wafer surface on the
other end.

      The figure shows a new design for such a printed circuit.  A
U-shaped metal land is expanded from each one of the holes where a
wire at ground potential is to be soldered. This U-shaped metal land
surrounds each one of the holes where a wire at a 'hot' potential
will be soldered. This is achieved for wires of cables connected to
test apparatus, as well as tips touching the wafer. For the
end-to-end probing system, good ground potential continuity is thus
assured, making the parametric test less sensitive to parasitic
phenomena.

      This new design integrates in a general attempt to increase
accuracy of the measuring of small capacitance on a wafer, by
minimizing parasitic interference induced by test apparatus and
probing system.  It permits the reduction of cable lengths,
4-wire-type measurement, VHF-type multiplexing of the wires, floating
potential of the wafer holder, etc.  Overall parasitic capacitance
between cap-meter and wafer tips has been thus reduced to 20 pF at 1
MHz test frequency.