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Focused Ion Beam Right Angle Sample Preparation Technique

IP.com Disclosure Number: IPCOM000109801D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 3 page(s) / 76K

Publishing Venue

IBM

Related People

Childs, KD: AUTHOR [+4]

Abstract

The materials analysis of semiconductor devices and packages often require a detailed examination of specific regions of a sample, including buried layers and interfaces. A difficulty in preparing such samples is the removal of material over such a region of interest with sufficient accuracy and precision, and without disturbing the region of interest, to allow subsequent analysis of the buried area. For example, to acquire an Auger sputter depth profile of a small area, buried interface requires the over-layer be thinned within a few thousand angstroms of the interface. This is a hit or miss proposition with standard sample preparation techniques, such as parallel polishing.

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Focused Ion Beam Right Angle Sample Preparation Technique

       The materials analysis of semiconductor devices and
packages often require a detailed examination of specific regions of
a sample, including buried layers and interfaces.  A difficulty in
preparing such samples is the removal of material over such a region
of interest with sufficient accuracy and precision, and without
disturbing the region of interest, to allow subsequent analysis of
the buried area.  For example, to acquire an Auger sputter depth
profile of a small area, buried interface requires the over-layer be
thinned within a few thousand angstroms of the interface.  This is a
hit or miss proposition with standard sample preparation techniques,
such as parallel polishing.  If the remaining over-layer is too
thick, then the resulting sputter depth profile will be unsuccessful
because of cone formation or loss of depth resolution.  If the
polishing proceeds too deeply, the area of interest is lost.

      A solution to this problem is a combination of standard polish
cross-sectional sample preparation and right angle FIB (focused ion
beam) sputtering.  In this technique, the sample is positioned as if
to prepare a standard cross-sectional sample.  Instead of polishing
into the feature of interest as one would with a standard cross
section, one edge of the sample is polished near to the area of
interest (within a few microns).  The other side of the sample is
polished so that the entire sa...