Multidimensional sensing system for atomic force microscopy

• US 20020104963A1
• Filed: 07/18/2001
• Published: 08/08/2002
• Est. Priority Date: 09/26/1998
• Status: Abandoned Application

• Current Assignee: Vladimir Mancevski
• Original Assignee: Vladimir Mancevski
• Inventors: Mancevski, Vladimir
• Application Number:
  US09/907,855
• Publication Number:
  US 20020104963A1
• Time in Patent Office: Days
• US Class Current: 250/306
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01Q 20/02 by optical means

Abstract

A six degree of freedom atomic force microscope (6-DOF AFM) is provided by the present invention. This 6-DOF AFM includes an AFM cantilever coupled to an AFM tip wherein the AFM tip deflects the cantilever in response to topographical changes on a sample. The AFM cantilever is illuminated by a collimated light beam generated by a collimated light source. The collimated light is reflected by the top surface of the AFM cantilever towards a PSD placed in the path of the reflected collimated light beam. The PSD produces an output containing data representing a deflection of the AFM cantilever. This output is processed by a data acquisition system to produce a representation of the topographical changes of the sample.

Claims

1. A six-degrees-of-freedom sensing system for sensing the motion of a rectangular-shaped cantilever, which is 35 μ

m wide and 350 μ

m long, during an atomic force microscopy scan of a sample fixed to a ground reference, comprising;

a piezoelectric transducer stage coupled to said cantilever, said piezoelectric transducer stage being capable of moving and positioning said cantilever in three directions and in three angular orientations, wherein said three directions are each perpendicular to each other and said three angular orientations are about each of said three directions, respectively, such that said piezoelectric transducer stage can provide three dimensional displacement with six-degrees-of-freedom for positioning said cantilever relative to said sample, wherein said piezoelectric transducer stage provides a 80 μ

m range of displacement for each of two directions of said three directions, and wherein said piezoelectric transducer stage provides a 9 μ

m range of displacement for a third direction of said three directions;

a pair of narrow-beam light emitting diode lasers fixed to said piezoelectric transducer stage such that a slope of light beams emitted from said narrow-beam lasers is maintained at a constant angle relative to said ground reference as said piezoelectric transducer stage moves said cantilever, each of said narrow-beam lasers being adapted to emit a collimated light beam having a diameter of less than 35 μ

m;

a wide-beam light emitting diode laser fixed to said ground reference, said wide-beam light emitting diode laser being adapted to emit a collimated light beam having a diameter of 100 μ

m;

a nonreflective region of said cantilever where said light beam from said wide-beam laser hits said cantilever over said predetermined range of motion of said cantilever;

two reflective marks disposed within said nonreflective region of said cantilever, each of said reflective marks having a diameter of less than 35 μ

m, and said reflective marks being centered and aligned along said cantilever'"'"'s length;

a two-dimensional continuous position-sensitive detector (PSD) fixed to said ground reference at a position such that reflections of light beams emitted from said lasers off of said cantilever strike said PSD for a predetermined range of motion of said cantilever, said PSD having a 5 mm by 5 mm sensor area;

a PSD signal processing circuit electrically connected to said PSD; and

a data acquisition system electrically connected to said PSD signal processing circuit, said data acquisition system being adapted to acquire and store signals from PSD signal processing circuit.