Metrological scanning probe microscope

• US 9,804,193 B2
• Filed: 11/03/2015
• Issued: 10/31/2017
• Est. Priority Date: 03/12/2014
• Status: Active Grant

• Current Assignee: Oxford Instruments Asylum Research Inc (Oxford Instruments PLC)
• Original Assignee: Oxford Instruments Asylum Research Inc (Oxford Instruments PLC)
• Inventors: Labuda, Aleksander, Walters, Deron, Cleveland, Jason, Proksch, Roger
• Primary Examiner(s): Ippolito, Nicole
• Assistant Examiner(s): Chang, Hanway
• Application Number:
  US14/931,625
• Publication Number:
  US 20160169937A1
• Time in Patent Office: 728 Days
• Field of Search: 850 1, 850 5, 850 6, 850 21, 850 33, 850 40
• CPC Class Codes: G01Q 20/02 by optical means

Abstract

This invention relates to a metrological scanning probe microscope system combining an SPM which employs an optical lever arrangement to measure displacement of the probe indirectly with another SPM which measures the displacement of the probe directly through the use of an interferometric detection scheme.

Claims

1. An atomic force microscope system with two optical beam positioning units operating to characterize a sample, comprising:

an atomic force microscope probe with a tip at one end of the cantilever;

a sample which is located below the tip of the cantilever;

an objective lens which allows optical viewing in an area of the cantilever or the sample, directs a light beam to the back of the cantilever opposite the tip and obtains a return beam from the cantilever indicative of the movement of the cantilever;

two dichroic mirrors, one of which receives a beam from the first optical beam positioning unit and in turn directs the beam to the objective lens, and the other of which receives a beam from the second optical beam positioning unit and in turn directs the beam to the objective lens;

a first optical beam positioning unit, comprising;

a light source with a lens emitting an infrared beam directed at a steering mirror that is rotatable in two orthogonal axes that are parallel to the mirror'"'"'s surface, one of such axes lying within the plane of incidence wherein lie both the infrared beam and the reflection of such beam;

focusing the axial position of the infrared beam reflected from the mirror on the back of the cantilever opposite the tip by pitching and yawing the steering mirror so that the physical pivot where the two orthogonal axes intersect coincides with point of incidence where the infrared beam is reflected from the mirror;

a lens group which collimates the infrared beam reflected from the steering mirror and directs it to a polarizing beamsplitter and quarter-waveplate and from which it is directed outside the first optical beam positioning unit to a dichroic mirror; and

the quarter-waveplate and polarizing beamsplitter which receive from the objective lens the return beam from the cantilever indicative of the movement of the cantilever and direct the beam to a photodetector;

a second optical beam positioning unit, comprising;

a light source with a lens emitting an beam in the blue end of the visible spectrum directed at a steering mirror that is rotatable in two orthogonal axes that are parallel to the mirror'"'"'s surface, one of such axes lying within the plane of incidence wherein lie both the blue beam and the reflection of such beam;

focusing the axial position of the blue beam reflected from the mirror on the base of the probe opposite the tip by pitching and yawing the steering mirror so that the physical pivot where the two orthogonal axes intersect coincides with point of incidence where the infrared beam is reflected from the mirror; and

a lens group which collimates the blue beam reflected from the steering mirror and directs it outside the second optical beam positioning unit to a dichroic mirror.

2. The system as in claim 1 wherein said beam in the blue end of the visible spectrum is a beam with a wave length of 405 nm.

3. A metrological scanning probe microscope system with two optical beam positioning units operating to characterize a sample, comprising:

a scanning probe microscope with scanning probe microscope probe having a tip at one end of the cantilever;

a laser doppler vibrometer with a HeNe laser;

a sample which is located below the tip of the cantilever;

an objective lens which allows optical viewing in an area of the cantilever or the sample, directs light beams from the scanning probe microscope and the laser doppler vibrometer to the back of the cantilever opposite the tip and obtains a return beam from the cantilever indicative of the movement of the cantilever;

an infrared dichroic window which;

receives a beam from the scanning probe microscope and in turn directs the beam to the objective lens, and

passes a beam from the laser doppler vibrometer which beam is directed to the objective lens;

a first optical beam positioning unit, comprising;

said scanning probe microscope which comprising;

a light source emitting an infrared beam;

a polarizing beamsplitter and quarter-waveplate which receive said infrared beam and direct it outside the first optical beam positioning unit to said infrared dichroic window; and

a quarter-waveplate and polarizing beamsplitter which receive from the objective lens the return beam from the cantilever indicative of the movement of the cantilever and direct the beam to a photodetector;

a second optical beam positioning unit, which comprises;

said laser doppler vibrometer emitting laser light;

a red dichroic mirror which reflects said laser light to said infrared dichroic window outside the second optical beam positioning unit.