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Scanning probe microscope

Foreign code F120006409
File No. 2008-050EP
Posted date Apr 6, 2012
Country EPO
Application number 10735586
Gazette No. 2392930
Gazette No. 2392930
Date of filing Jan 14, 2010
Gazette Date Dec 7, 2011
Gazette Date Jan 3, 2018
International application number JP2010000164
International publication number WO2010087114
Date of international filing Jan 14, 2010
Date of international publication Aug 5, 2010
Priority data
  • P2009-021675 (Feb 2, 2009) JP
  • 2010WO-JP00164 (Jan 14, 2010) WO
Title Scanning probe microscope
Abstract (EP2392930)
An atomic force microscope (AFM) (1) is one type of SPM, and detects a resonance frequency shift as an amount of interaction between a probe and a sample.
The AFM (1) performs distance modulation control while performing feedback control of a probe-sample distance so as to keep the amount of interaction constant.
The distance modulation control varies the probe-sample distance at a distance modulation frequency higher than a response speed of the feedback control.
The AFM (1) further acquires the interaction amounts detected during the variation of the probe-sample distance by the distance modulation control while performing relative scanning between the probe and the sample, and detects a distribution of the interaction amounts in a three-dimensional space having a dimension within a scanning range and a thickness within a variation range of the probe-sample distance.
The present invention thereby provides a scanning probe microscope (SPM) capable of preferably measuring the distribution of the interactions between the probe and the sample in the three-dimensional space while performing stable probe position control.
Scope of claims [claim1]
1. A scanning probe microscope comprising: a probe; a scanner which performs relative scanning between the probe and a sample; a displacement sensor which detects a displacement of the probe; an interaction detecting section which detects an amount of interaction generated by an interaction between the probe and the sample and representing magnitude of the interaction based on a signal detected by the displacement sensor; a feedback control section which performs feedback control of a probe-sample distance as a distance between the probe and the sample such that the amount of interaction detected by the interaction detecting section is kept constant; a distance modulation control section which performs distance modulation control to vary the probe-sample distance at a distance modulation frequency higher than a response speed of the feedback control; and a three-dimensional distribution detecting section which detects a distribution of the interaction amounts in a three-dimensional space having a dimension within a scanning range and a thickness within a variation range of the probe-sample distance from the interaction amounts detected during the variation of the probe-sample distance by the distance modulation control while performing the relative scanning between the probe and the sample.
[claim2]
2. The scanning probe microscope according to claim 1,
wherein the distance modulation control section varies the probe-sample distance in a sinusoidal pattern along a time axis.
[claim3]
3. The scanning probe microscope according to claim 1,
wherein the feedback control section generates a drive signal for driving the scanner,
the distance modulation control section generates a distance modulation signal having the distance modulation frequency, and
the distance modulation signal is added to the drive signal.
[claim4]
4. The scanning probe microscope according to claim 1,
wherein the three-dimensional distribution detecting section separately acquires the distribution of the interaction amounts during the probe approach to the sample by the distance modulation control, and the distribution of the interaction amounts during the probe retraction from the sample by the distance modulation control.
[claim5]
5. The scanning probe microscope according to claim 1,
wherein the scanning probe microscope is an atomic force microscope, comprising a cantilever with the probe.
[claim6]
6. The scanning probe microscope according to claim 5,
wherein the atomic force microscope is a frequency modulation atomic force microscope, and the interaction detecting section detects a resonance frequency shift of the cantilever as the amount of interaction.
[claim7]
7. The scanning probe microscope according to claim 1, further comprising: a drift monitoring section which monitors the amount of interaction detected at a predetermined drift monitoring position, which is defined within the variation range of the probe-sample distance by the distance modulation control and at which the probe-sample distance increases, as an indication of a drift of the amount of interaction; and a drift canceling section which cancels the drift of the amount of interaction based on the amount of interaction monitored at the drift monitoring position by the drift monitoring section.
[claim8]
8. The scanning probe microscope according to claim 1, further comprising a distribution data processing section which processes data of the distribution of the interaction amounts in the three-dimensional space obtained by the three-dimensional distribution detecting section,
wherein the distribution data processing section obtains the distribution of the interaction amounts on a plane where the probe-sample distance is constant.
[claim9]
9. The scanning probe microscope according to claim 1, further comprising a distribution data processing section which processes data of the distribution of the interaction amounts in the three-dimensional space obtained by the three-dimensional distribution detecting section,
wherein the distribution data processing section obtains a plurality of representative values of the interaction amounts respectively on a plurality of planes where the probe-sample distances differ from each other, to thereby obtain a variation in the representative values during the probe approach to the sample.
[claim10]
10. The scanning probe microscope according to claim 1, further comprising a distribution data processing section which processes data of the distribution of the interaction amounts in the three-dimensional space obtained by the three-dimensional distribution detecting section,
wherein the distribution data processing section obtains the distribution of the interaction amounts on a cut plane obtained by cutting the three-dimensional space along a plane intersecting with a surface of the sample.
[claim11]
11. The scanning probe microscope according to claim 1, further comprising a distribution data processing section which processes data of the distribution of the interaction amounts in the three-dimensional space obtained by the three-dimensional distribution detecting section,
wherein the distribution data processing section obtains a variation in the interaction amounts along a line intersecting with a surface of the sample at a plurality of different positions on the sample.
[claim12]
12. An observation method for a scanning probe microscope, comprising: performing relative scanning between a probe and a sample by moving the probe and the sample close to each other; detecting a displacement of the probe; detecting an amount of interaction generated by an interaction between the probe and the sample and representing magnitude of the interaction based on a detected signal; performing feedback control of a probe-sample distance as a distance between the probe and the sample such that the amount of interaction is kept constant; performing distance modulation control to vary the probe-sample distance at a distance modulation frequency higher than a response speed of the feedback control; and detecting a distribution of the interaction amounts in a three-dimensional space having a dimension within a scanning range and a thickness within a variation range of the probe-sample distance from the interaction amounts detected during the variation of the probe-sample distance by the distance modulation control while performing the relative scanning between the probe and the sample.
[claim13]
13. An observation program for a scanning probe microscope, causing a computer to execute: a process of performing relative scanning between a probe and a sample by moving the probe and the sample close to each other; a process of detecting a displacement of the probe; a process of detecting an amount of interaction generated by an interaction between the probe and the sample and representing magnitude of the interaction based on a detected signal; a process of performing feedback control of a probe-sample distance as a distance between the probe and the sample such that the amount of interaction is kept constant; a process of performing distance modulation control to vary the probe-sample distance at a distance modulation frequency higher than a response speed of the feedback control; and a process of detecting a distribution of the interaction amounts in a three-dimensional space having a dimension within a scanning range and a thickness within a variation range of the probe-sample distance from the interaction amounts detected during the variation of the probe-sample distance by the distance modulation control while performing the relative scanning between the probe and the sample.
  • Applicant
  • TOHOKU UNIVERSITY
  • Inventor
  • FUKUMA TAKESHI
  • UEDA YASUMASA
IPC(International Patent Classification)
Specified countries (EP2392930)
Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR
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