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Browse Prior Art Database

SEM Electron Charging Eliminator

IP.com Disclosure Number: IPCOM000109299D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Fredericks, EC: AUTHOR [+2]

Abstract

Field accelerated and magnetically bunched electron beams used in electron microscopy equipment will deposit charges on the specimens under investigation. In case of insulator material, these charges cannot be properly dissipated and result in a surface charge phenomena which will interact with the low energy secondary electrons, deflecting their path and hampering their collection by the electron detector fields.

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SEM Electron Charging Eliminator

       Field accelerated and magnetically bunched electron beams
used in electron microscopy equipment will deposit charges on the
specimens under investigation.  In case of insulator material, these
charges cannot be properly dissipated and result in a surface charge
phenomena which will interact with the low energy secondary
electrons, deflecting their path and hampering their collection by
the electron detector fields.

      Thermal excitation of insulating layers will improve the
conduction and the dissipation of the electronic charges, provided
that the temperatures used are on the order of 85-90oC.

      Fig. 1 shows a specially designed semiconductor stage.  A
semiconductor/solid-state thermoelectric heater-cooler (a) is used to
cool/ warm up the specimen (wafer) holder (b).  Heating and
subsequent cooling is achieved by inverting the polarity at the
heater electrical connections (c) and (d).

      Fig. 2 shows another embodiment of the disclosure.  A small
solid-state IR laser is used as a radiation source to selectively
heat specific areas of the sample under evaluation.  Cooling is
achieved through heat sinking of the whole wafer using thermal
conduction.  Other lasers can be used: if they are contained within
the vacuum environment of the SEM main evacuated chamber.

      This invention provides a method for reduction/elimination of
surface charge through thermal excitation.  In addition, a prototyp...