# US 10,502,761 B2 · Method and apparatus of operating a scanning probe microscope

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,502,761 B2
- Document ID: US10502761B2
- Status: Granted
- Kind: B2
- Application number: 15/449,584
- Filed: 2017-03-03
- Published: 2017-08-24
- Granted: 2019-12-10
- Earliest claimed: 2008-11-13
- Assignees: Bruker Nano, Inc.
- Applicants: Bruker Nano, Inc.
- Inventors: Yan Hu; Shuiqing Hu; Chanmin Su
- Web page: https://patentgrep.com/patent/US10502761B2

## CPC

- G01Q 20/00: Monitoring the movement or position of the probe
- B82Y 35/00: Methods or apparatus for measurement or analysis of nanostructures
- G01Q 10/065: {Feedback mechanisms, i.e. wherein the signal for driving the probe is modified by a signal coming from the probe itself}
- G01Q 20/02: by optical means
- G01Q 60/24: AFM [Atomic Force Microscopy] or apparatus therefor, e.g. AFM probes
- G01Q 60/30: Scanning potential microscopy
- G01Q 60/32: AC mode
- G01Q 60/34: Tapping mode
- G01Q: SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

An improved mode of AFM imaging (Peak Force Tapping (PFT) Mode) uses force as the feedback variable to reduce tip-sample interaction forces while maintaining scan speeds achievable by all existing AFM operating modes. Sample imaging and mechanical property mapping are achieved with improved resolution and high sample throughput, with the mode workable across varying environments, including gaseous, fluidic and vacuum.

## Claims

### Claim 1

A method of operating a scanning probe microscope (SPM) comprising:
interacting a tip of a probe of the SPM with a sample; then
terminating the interaction, resulting in a decaying probe oscillation;
repeating the interaction before ringdown of the decaying probe oscillation is substantially complete; and
detecting motion of the probe during the interaction step;
determining an instantaneous force on the tip based on the detecting step;
using the instantaneous force as a feedback control parameter to operate the SPM; and
further comprising determining a synchronization distance and using the synchronization distance to determine the instantaneous force.

### Claim 2 (depends on 1)

The method of claim 1, wherein the synchronization distance is determined using one of A) measuring the phase delay between the detected motion and a drive signal of the oscillating step, and B) measuring a distance between initiating a period of the drive signal and an instant of interaction between the probe and the sample.

### Claim 3 (depends on 1)

The method of claim 1, wherein the synchronization distance is determined using a window.

### Claim 4 (depends on 1)

The method of claim 1, wherein the determining step includes subtracting that portion of the detected motion caused by parasitic forces from the detected motion.

### Claim 5 (depends on 4)

The method of claim 4, wherein a minimum controllable force upon performing the subtraction step is at least about an order of magnitude less than a minimum controllable force without perforating the subtraction step.

### Claim 6 (depends on 5)

The method of claim 5, wherein the minimum controllable force is about 1 pN when the cantilever has a length equal to about 100 microns and a spring constant of about 0.01 N/m.

### Claim 7 (depends on 4)

The method of claim 4, wherein the parasitic forces are caused by a hydrodynamic background.