Imaging a gap between sample and probe of a scanning probe microscope in a substantially horizontal side view

Patent metadata

Field	Value
Publication number	US-10684307-B2
Application number	US-201715817448-A
Country	US
Kind code	B2
Filing date	Nov 20, 2017
Priority date	Nov 22, 2016
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

A scanning probe microscope analyses a sample by moving a probe and the sample relative to one another. The scanning probe microscope includes a detection unit for detecting an image of a gap between the sample and the probe in a substantially horizontal side view.

First claim

The invention claimed is:

1. A scanning probe microscope using scanning probe microscopy for analyzing a sample by moving a probe and the sample relative to one another, the scanning probe microscope comprising:
a detection unit for detecting an image of a gap between the sample and the probe in a substantially horizontal side view;
an optical system at least partially between the gap and the detection unit, wherein the optical system is a telecentric optical system that provides a magnification independent of a distance between the gap and the detection unit;
a drive unit configured for moving at least one of the probe and the sample for mutually approaching the probe and the sample based on the image of the gap between the sample and the probe,
wherein the optical system comprises at least one lens and an aperture through which an electromagnetic radiation beam, after propagating through the gap, propagates before it reaches the detection unit; and
an illumination unit configured for illuminating the gap with the electromagnetic radiation beam from a substantially horizontal side position,
wherein the detection unit and the illumination unit are arranged so that the electromagnetic radiation beam propagates from the illumination unit through the gap to the detection unit.

2. The scanning probe microscope according to claim 1 , wherein the image in the substantially horizontal side view is detected at an angle of less than 5° to a horizontal axis.

3. The scanning probe microscope according to claim 1 ,
wherein the drive unit controllably adjusts a separation between the probe and the sample from an initial distance to a final distance of less than 1 mm, based on the detected image of the gap.

4. The scanning probe microscope according to claim 3 , wherein the drive unit is configured for moving at least one of the probe and the sample for mutually approaching probe and sample from the initial distance to an intermediate distance with a first velocity and subsequently from the intermediate distance to the final distance with a second velocity smaller than the first velocity based on the detected image of the gap.

5. The scanning probe microscope according to claim 1 , wherein the detection unit is configured for being capable of detecting a size of the gap for samples of different sizes without readjustment.

6. The scanning probe microscope according to claim 1 , comprising at least one of the following features:
wherein the illumination unit is configured for homogeneously illuminating the gap;
wherein an optical path between the illumination unit and the detection unit is an unfolded linear optical path;
wherein an optical path between the illumination unit and the detection unit is a folded optical path comprising one or two folding positions.

7. The scanning probe microscope according to claim 1 , wherein at least one lens is located at a distance from the detection unit which corresponds to a focal length of the at least one lens.

8. The scanning probe microscope according to claim 1 , further comprising:
a determining unit configured for determining a quantitative value of the distance between the sample and the probe based on the detected image.

9. The scanning probe microscope according to claim 1 , further comprising:
at least two detection units arranged around an array composed of the probe and the sample, each detecting unit being arranged for detecting a substantially horizontal side view of the gap from another direction.

10. The scanning probe microscope according to claim 1 , further comprising:
an optical manipulation unit configured for manipulating electromagnetic radiation propagating towards the detection unit in a grinded prism for generating a set of parallel rays of electromagnetic radiation with homogeneous intensity.

11. A method of monitoring a gap between a probe and a sample of a scanning probe microscope, wherein the scanning probe microscope uses scanning probe microscopy to analyze a sample where the scanning probe microscope comprises a drive unit, a detection unit, an illumination unit and an optical system, the optical system at least partially between the gap and the detection unit, wherein the optical system is a telecentric optical system that provides a magnification independent of a distance between the gap and the detection unit, and wherein the optical system comprises at least one lens and an aperture through which an electromagnetic radiation beam, after propagating through the gap, propagates before it reaches the detection unit, the method comprising:
providing the sample separated by the gap from the probe;
illuminating, by the illumination unit, the gap with the electromagnetic radiation beam from a substantially horizontal side position, so that the electromagnetic radiation beam propagates from the illumination unit through the gap to the detection unit; and
detecting, using the detection unit, an image of the gap in a substantially horizontal side view; and
manipulating, by the drive unit, a distance between the probe and the sample based on the detected image of the gap.

Assignees

• Anton Paar Gmbh

Inventors

• Koller Daniel
• Gomez-Casado Alberto
• Brandner Markus

Classifications

• G01Q60/24

  AFM [Atomic Force Microscopy] or apparatus therefor, e.g. AFM probes · CPC title

• G01Q20/00

  Monitoring the movement or position of the probe · CPC title

• G01Q10/04 Primary

  Fine scanning or positioning · CPC title

• G01Q10/06

  Circuits or algorithms therefor · CPC title

• G01Q30/02

  Non-SPM analysing devices, e.g. SEM [Scanning Electron Microscope], spectrometer or optical microscope · CPC title