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Scanning Kelvin Probe Force Microscope and its Use in Failure Analysis for Locating Defects

IP.com Disclosure Number: IPCOM000109691D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Related People

Hwang, T: AUTHOR [+4]

Abstract

The Scanning Kelvin Probe Force Microscope (SKPFM) is a powerful new instrument that allows for the simultaneous measurement of surface potentials and surface topography. This is achieved with very high resolution (10 nm laterally and 0.5 nm vertically) in a noncontact/nondestructive manner under ambient conditions on either conductive or nonconductive materials.

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Scanning Kelvin Probe Force Microscope and its Use in Failure Analysis for Locating Defects

       The Scanning Kelvin Probe Force Microscope (SKPFM) is a
powerful new instrument that allows for the simultaneous measurement
of surface potentials and surface topography.  This is achieved with
very high resolution (10 nm laterally and 0.5 nm vertically) in a
noncontact/nondestructive manner under ambient conditions on either
conductive or nonconductive materials.

      Because the SKPFM can measure surface potentials with high
resolution, it is able to spatially locate failures caused by charge,
dislocations, cracks, defects and material composition.  This has
been verified by measuring known failed devices.

      For failure analysis, the tool is used to image a large region
of a chip which includes both the failed device along with the many
known good devices which surround it.  In most cases the failed
device will have a much different surface potential then the good
devices around it, and the abnormal surface potential is usually
confined to a region much smaller than the device size.  Our results
have found or verified leakages caused by charge, oxided charge, a
crack perpendicular to the surface and contamination between a
Schottky device and the substrate.  It also found or verified two
different cases of device shorting; in one case the emitter and base
were shorted in the semiconductor and in the other they were shorted
through the metalization.

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