Browse Prior Art Database

Measurement of Defects in Resist Layers

IP.com Disclosure Number: IPCOM000103517D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 68K

Publishing Venue

IBM

Related People

Hohn, F: AUTHOR [+4]

Abstract

A scanning electron microscope (SEM) is operated in a sample current mode in order to detect defects in resist-coated silicon wafers. The resulting SEM photo displays defect-free areas of the resist film as a black background, with defects visible as bright white dots. This can be used to provide high resolution detection of defects and sensitivity toward the number of defects and their size distribution.

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Measurement of Defects in Resist Layers

      A scanning electron microscope (SEM) is operated in a sample
current mode in order to detect defects in resist-coated silicon
wafers.  The resulting SEM photo displays defect-free areas of the
resist film as a black background, with defects visible as bright
white dots.  This can be used to provide high resolution detection of
defects and sensitivity toward the number of defects and their size
distribution.

      In the sample current mode of defect testing, the electrical
current absorbed by the sample as the electron beam is rastered
across the surface is a measure of the quality of the resist layer.
Defects exist where the electron beam can reach the silicon surface,
and are registered as a sample current.  Defect- free areas of the
insulating resist film prevent the electrons from reaching the
silicon surface.  No detectable beam current is therefore observed
because the resist is insulating at the beam potentials used.  This
inhibits absorption of the electron beam across the resist.
Continuous defects, such as pinholes or cracks which extend through
the resist film to the silicon surface, are detected because they
provide a path for the electrons from the resist surface to the
conductive silicon surface.

      The SEM photographs can be visually examined in order to
provide a count of the number of pinholes in the resist, or to
provide qualitative information showing relative changes in defect
density. ...