Browse Prior Art Database

Scanning Force Microscope Objective

IP.com Disclosure Number: IPCOM000106978D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 3 page(s) / 105K

Publishing Venue

IBM

Related People

Martin, Y: AUTHOR [+2]

Abstract

A new Scanning Force Microscope (SFM) is designed as a small objective like unit, destined to be fitted to an optical microscope. This new objective shall extend the capabilities of the optical microscope by allowing imaging and sensitive topographic measurement down to the nanometer scale, in a flexible and simple manner. Description and operation of the SFM objective are given.

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Scanning Force Microscope Objective

       A new Scanning Force Microscope (SFM) is designed as a
small objective like unit, destined to be fitted to an optical
microscope.  This new objective shall extend the capabilities of the
optical microscope by allowing imaging and sensitive topographic
measurement down to the nanometer scale, in a flexible and simple
manner.  Description and operation of the SFM objective are given.

      The Scanning Force Microscope is a novel and flexible tool that
allows non-destructive examination of the surface of devices on a
nanometer scale (1).  Its unique capabilities include the measurement
of surface roughness down to a few angstrom, nanometer profiling and
metrology, magnetic imaging and electrical measurements on a
submicron scale.  The proposed Scanning Force Microscope Objective
shall overcome several disadvantages of present commercial
instruments: which can only inspect small samples, typically less
than an inch in size, optical viewing for pre-alignment is limited,
and the instruments are large and complex workstations.

      A schematic diagram of the SFM objective is shown.  One of the
key elements for the miniaturization of the objective is the new
optical detection system.  Referring to the figure, it consists of a
single- mode optical fiber 1 pig-tailed to a laser diode 2 which also
contains an integrated photo-detector.  The radiation coming from the
laser diode and fiber reflects off the vibrating tip-lever 3.  Part
of the reflected radiation reenters the fiber and modulates the laser
light.  The part that reenters is strongly a result of interferences
between the end of the fiber and the lever, and, thus, it is mostly a
periodic function of the spacing d between these two elements, with a
period g/2.  Detecting this reentering light with the photo-detector,
one can detect vibrations of the tip with a sensitivity of about 1
Angstrom in a 10 kHz bandwidth.

      The detection is close to optimum at spacing d up to 20 mm.
This loose tolerance makes the alignment between the cantilever and
the fiber fairly easy in the Z direction. The fiber is held by a
bimorph 4 (used to set d so that the detection sensitivity is
maximum) and a thin glass plate 5; both bimorph and glass plate are
epoxied to a ring 6 which is attached to the XYZ scanner 7.  The XYZ
scanner is a piezo tube with s...