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Hole Pattern Writing and Lift Off Technique Using STM

IP.com Disclosure Number: IPCOM000122007D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Binnig, G: AUTHOR [+2]

Abstract

A scanning tunnelling microscope (STM) is capable of forming a low- voltage submicron beam of extremely high density and thus may be used to advantage for microlithographical applications.

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Hole Pattern Writing and Lift Off Technique Using STM

      A scanning tunnelling microscope (STM) is capable of
forming a low- voltage submicron beam of extremely high density and
thus may be used to advantage for microlithographical applications.

      Structuring in the nanometer range requires a resist which may
be deposited on the substrate as an extremely thin homogeneous layer.

      By applying an aqueous solution of cetyltrimethylammonium
bromide (CETAVLON*) with a concentration of 0.1 mg/ml to highly
oriented pyrolytic graphite, such an ultrathin molecular layer of
about 1 nm thickness may be prepared on an atomically planar
substrate. The STM is used as a control instrument for the resist
layer and its modification by means of pulses (electronic etching)
(Fig. 1A).  By short voltage pulses (about 5 V and about 1 ms
duration) applied with the aid of the STM, fine holes of about 3 nm
diameter are opened in the resist layer.

      With CETAVLON as a resist, such holes remain stable for hours.
In addition, layer material is only removed from inside the holes,
thus baring an atomically planar substrate without any destruction.
This treatment polymerizes the ejected material and stabilizes the
structure, in particular, the hole edges.

      The aspect ratio obtained by this hole pattern write method is
typically 0.6 n/3.0 n = 0.2.

      This approach yields a most finely structured mask for applying
various materials to the substrate by co...