Browse Prior Art Database

Failure Analysis Etch Tank

IP.com Disclosure Number: IPCOM000118759D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 86K

Publishing Venue

IBM

Related People

Wells, RH: AUTHOR

Abstract

Disclosed is an etch tank suitable for etching portions of a wafer using very small quantities of fluid etchant designed for failure analysis or experimental work.

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This is the abbreviated version, containing approximately 52% of the total text.

Failure Analysis Etch Tank

      Disclosed is an etch tank suitable for etching portions of a
wafer using very small quantities of fluid etchant designed for
failure analysis or experimental work.

      Often, in failure analysis and inline characterization, it is
necessary to delay the chips.  When the samples are submitted as
wafers, it becomes necessary to break the wafer into chip-size
pieces.  It then  becomes impossible to do any further testing on
that wafer.  The invention allows portions of wafers, rows of wafers,
and even individual  chips to be delayered leaving the rest of the
wafer intact and testable.  A further problem solved is the large
quantify of chemical needed to etch wafers in conventional equipment.

      Failure analysis is, for the most part, a destructive
technique.  This usually is not a concern with module-level fails but
can be a shortcoming when the problem and its solution are focused at
wafer level and wafer fabrication.  Examples of when it would be
desirable to keep the wafer testable after delayering selected chips
include: when the results of the analysis would indicate additional
testing, when it is being determined that the problem lies in certain
areas, when NDF occur, and when FIB repair work is done and it would
be valuable to do subsequent wafer level processing.

      Additionally, it can be desirable to retest the wafer after
analysis with a changed set of test parameters, based on the analysis
results.

      In a first embodiment, a tank is fabricated that is half the
diameter of a wafer and designed such that the volume of chemical is
minimal (Figs. 1A, B and C).  Any outer ro...