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Metal Charge layer for SEM measurements ,optical defect inspection, laser and FIB defect Repair and Defect protection_

IP.com Disclosure Number: IPCOM000013830D
Original Publication Date: 2000-Nov-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Abstract

Title of disclosure

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This is the abbreviated version, containing approximately 51% of the total text.

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  Metal Charge layer for SEM measurements ,optical defect inspection, laser and FIB defect Repair and Defect protection_

Title of disclosure

Metal Charge layer for SEM measurements ,optical defect inspection,
laser and FIB defect Repair and Defect protection

Idea of disclosure

Measurement of high end products in optical mask manufacture is
limited by the ability of optical microscopes to resolve below .7
microns and to measure accurately. It is required today to use SEM
measurements on features that are smaller than .7 microns to gain
repeatable and accurate results. This technique to date is
destructive because of defects generated in non clean room SEM areas
and is extremely inaccurate unless a charge dissipating layer is
applied to the surface being analyzed. Stripping the charging layer
can degrade the mask and create additional defects. Due to this
degrade caused by strip the part must go to an inspection tool to
locate any additional defects. If clear (missing material) defects
are found the plate must again be coated with a conductive layer so
processing with a focused ion beam (FIB) repair system can occur
without charging. In addition, adding a charge neutralizing layer to
a production part renders the part useless to typical defect
detection systems that find defects in the plate utilizing
transmitted light.

To aid the measurement task a thin (<100 angstrom) copper film is
sputtered on the production mask. Because the film is sputtered it is
very conformal and minimizes errors to side wall measurements that
are the critical features required. In addition, the sputtered film
acts as a charge dissipation layer. This charge dissipation layer
allows a typical Scanning Electron Microscope (SEM) tool to provide
superior accuracy of side wall feat...