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Photo-Optical Localization of Section Topographies On Silicon Wafers

IP.com Disclosure Number: IPCOM000101667D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Mirbach, E: AUTHOR

Abstract

In addition to the known Lang topography, section topographies are a valuable means for detecting crystal defects during the production of semiconductor devices. In the described example, selected regions on silicon wafers are localized by photo-optical means under Bragg reflection conditions.

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Photo-Optical Localization of Section Topographies On Silicon Wafers

       In addition to the known Lang topography, section
topographies are a valuable means for detecting crystal defects
during the production of semiconductor devices.  In the described
example, selected regions on silicon wafers are localized by
photo-optical means under Bragg reflection conditions.

      As shown in the schematic of Fig. 1, for the Lang topography,
the crystal to be examined and the photoplate are led under
reflection conditions through a relatively divergent X-ray bundle.
Lattice defects in the crystal (such as displacements and inclusions)
are projected on top of each other on the photoplate by blocking the
primary beam.  X-ray stereo topography provides information on the
spatial position of such lattice defects.

      For section topography, crystal and photoplate are not
transferred jointly during imaging, so that a primary beam collector
is not required (Fig. 2).  The collimator gap is reduced to / 5 mm,
and the distance of photoplate and crystal is minimal.

      The photomaterial consists of high-resolution plates with an
emulsion thickness of 10 mm.  The exposure time is about 30 to 60
minutes.  The spacing between primary beam and reflected beam on the
photoplate permits several sections to be imaged successively.

      As a result of the collimator gap of 5 mm, it is extremely
difficult and time-consuming to localize wafer structures under
reflec...