Browse Prior Art Database

SEM Magnification Standard

IP.com Disclosure Number: IPCOM000052469D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Aliotta, CF: AUTHOR [+2]

Abstract

A grating or corrugated structure may be used as a calibration standard for SEM (Scanning Electron Microscope) magnification.

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SEM Magnification Standard

A grating or corrugated structure may be used as a calibration standard for SEM (Scanning Electron Microscope) magnification.

An easily manufactured structure is illustrated (Fig. 1). Resist grating 10 is fabricated on top of a substrate 12 by laser holographic exposure and subsequent development. A chrome or gold coating 14 is then deposited on top of the resist grating.

Such a structure has the following advantages as a magnification standard.

1) It costs very little to manufacture.

2) The periodicity can be accurately predetermined during manufacure by geometrical constraints.

3) The average periodicity over a given area (say, a few square mm) may be easily measured at any time by determining the first- or higher order diffraction angles for monochromatic light incident normal to the grating plane. A monochromatic light source with wavelength less than the grating periodicity is the only optical equipment needed.

4) The grating lines can cover the entire surface of the standard and are easily identifiable. The National Bureau of Standards' (NBS) device requires a marker to locate a series of seven lines, and the marker is not easily located.

5) More lines are measurable at high magnification than with the NBS standard, so that the grating standard can be used at a higher magnification than the NBS standard.

6) Superposition of two holographic gratings at right angles to each other by successive exposures in the manufacturing process...