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Absolute Linewidth Calibration Standard with High Contrast for Scanning Electron Microscopes/Atomic Force Microscopes

IP.com Disclosure Number: IPCOM000118017D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Bayer, T: AUTHOR [+4]

Abstract

Disclosed is a calibration standard which allows for the calibration of Scanning Electron Microscopes (SEMs) and Scanning Probe Microscopes (SPMs) in their lateral scanning directions. Used are submicron patterns generated by holographic diffraction and with enhanced contrast achieved by dry etching pattern transfer.

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Absolute Linewidth Calibration Standard with High Contrast for Scanning
Electron Microscopes/Atomic Force Microscopes

      Disclosed is a calibration standard which allows for the
calibration of Scanning Electron Microscopes (SEMs) and Scanning
Probe Microscopes (SPMs) in their lateral scanning directions.  Used
are submicron patterns generated by holographic diffraction and with
enhanced contrast achieved by dry etching pattern transfer.

      Holography and light diffraction allow to maintain interference
patterns or line gratings of highest precision.  The precision of the
pitch of these line gratings is in the low nanometer range whereas
the grating constant is defined by the wavelength of the light used.
Both SEMs and SPMs require line edges of highest contrast.  For SEMs,
contrast is achieved by perpendicular edges showing at best no radius
of curvature  whereas for SPMs overhanging edges with a very low
radius of curvature  are advantageous.  Today's standards have very
bad edge properties and  thus provide only low contrast.

      Figs. 1 a) to d) show the proposed method for fabricating the
calibration standards.  The silicon wafer 1 in Fig. 1a) is covered by
an oxide (2), a nitride (3) and a structured photo resist layer (4)
representing a holographically fabricated diffraction grating.  The
primarily structured resist pattern has been isotropically etched in
an O(2)- plasma to broaden the area opened in the resist layer.  In

Fig. 1b), the...