Metrological scanning probe microscope

• US 10,338,096 B2
• Filed: 10/31/2017
• Issued: 07/02/2019
• 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 M
• Assistant Examiner(s): Chang, Hanway
• Application Number:
  US15/798,941
• Publication Number:
  US 20180128853A1
• Time in Patent Office: 609 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 that operates to characterize a sample, comprising:

an atomic force microscope probe having a cantilever with a tip;

an objective lens which allows optical viewing in an area near the sample, the objective lens operable to direct a light beam to a surface of the cantilever and to obtain a return beam from the surface,

the return beam being indicative of movement of the cantilever;

a first optical beam positioning unit, comprising;

a rotatable steering mirror that is rotatable in two orthogonal axes that are parallel to a reflecting surface of the steering mirror;

a light source emitting a first beam directed at the steering mirror, where the first beam has a first wavelength;

the steering mirror controlled to reflect the first beam on the surface of the cantilever opposite the tip, by pitching and yawing the steering mirror, and controlling a physical pivot where the two orthogonal axes intersect to coincide with a point of incidence where the first beam is reflected from the mirror;

a first mirror receiving the first beam from the first optical beam positioning unit and directing the first beam to the objective lens;

said first mirror receiving a reflection of the first beam from the surface of the cantilever, and

a first photodetector detecting a first light power of the first light beam reflected form the surface of the cantilever;

a second optical beam positioning unit, comprising;

a second light source emitting a second beam at a second wavelength different than the first wavelength;

a second rotatable steering mirror, that is rotatable in two orthogonal axes that are parallel to a reflecting surface of the rotatable steering mirror,

the second steering mirror controlled to reflect the second beam on the surface of the cantilever opposite the tip by pitching and yawing the second steering mirror and controlling a physical pivot where the two orthogonal axes intersect to coincide with a point of incidence where the second beam is reflected from the mirror; and

a second mirror receiving the second beam from the second optical beam positioning unit and directing the second beam to the objective lens; and

a second photodetector detecting a second light power of the second light beam reflected form the surface of the cantilever;

where both the first beam and the second beam are reflected from the surface of the cantilever; and

wherein said system is used for a functionality other than measuring probe displacement of the cantilever.

2. The system as in claim 1 wherein said First beam is at a red end of the optical spectrum and the second beam is at a blue end of the optical spectrum.

3. The system as in claim 2, wherein the first mirror and the second mirror are each selectively reflective of different optical spectra.

4. The system as in claim 1, wherein the first and second steering mirror have physical pivots in three-dimensional space which are tuned to set a desired relationship between an axial position of the focus and an angular orientation of the reflected light beam which are geometrically constrained to move along a defined surface.

5. The system as in claim 1, wherein the system combines the first beam and the second beam to measure interferometrically at least one object of interest.

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

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

a laser doppler vibrometer with a first laser;

an objective lens which is located to carry out optical viewing in an area of the cantilever,

the objective lens directing light beams from the scanning probe microscope and the laser doppler vibrometer to a surface of the cantilever opposite the tip and obtains a return beam from the cantilever indicative of the movement of the cantilever;

a first 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 a first beam;

a polarizing beamsplitter and quarter-waveplate which receive said first beam and direct said first beam outside the first optical beam positioning unit to said first 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 second dichroic mirror which reflects said laser light to said dichroic window outside the second optical beam positioning unit;

where the photodetector detects a position of the light beam on the probe and the probe'"'"'s deflection or oscillation; and

where the second optical beam positioning unit measures information about the probe interferometrically.

7. The system as in claim 6, wherein the first dichroic mirror is infrared.