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Browse Prior Art Database

Parallel Chip Test Cassette

IP.com Disclosure Number: IPCOM000119347D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Greschner, J: AUTHOR [+5]

Abstract

This article describes how a complete wafer is contacted by a contact wafer with micromechanical properties and how this allows testing the various chips on the wafer all at once. In addition, such an arrangement may be used during the subsequent burn-in test.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 96% of the total text.

Parallel Chip Test Cassette

      This article describes how a complete wafer is contacted
by a contact wafer with micromechanical properties and how this
allows testing the various chips on the wafer all at once. In
addition, such an arrangement may be used during the subsequent
burn-in test.

      A silicon contact wafer, whose surface is provided with etched
conductors and contacts, is used to simultaneously contact the
various chips on the wafer.  To ensure that the wafer to be tested is
contacted at the appropriate pressure, the contact wafer is
additionally provided with etched resilient tongues.  At the end of
each tongue there is a contact bump which is connected to the test
control means by the associated conductor on the contact wafer.

      The contact wafer is contained in a cassette into which the
wafer to be tested is inserted by means of a Z-chuck. The contacts of
the contact wafer are aligned to the C4 pads of the wafer to be
tested.  This may be done by standard optical methods using marks in
the contact wafer and, for example, by a window in the covering plate
of the cassette. After alignment, the contact wafer is pressed
downwards by resiliently mounted lift bolds or other means.  After
contact has been established, the chips on the wafer to be tested are
testable from the outside.  The connectors may be linked by flexible
means to a connector card and to the tester.

      The entire cassette may then be loaded into a burn-in stati...