# US 2016/0258979 A1 · Method and Apparatus of Operating a Scanning Probe Microscope

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- Number: US 2016/0258979 A1
- Document ID: US20160258979A1
- Status: Published application
- Kind: A1
- Application number: 15/057,963
- Filed: 2016-03-01
- Published: 2016-09-08
- Earliest claimed: 2008-11-13
- Assignees: Bruker Nano, Inc.
- Applicants: Bruker Nano, Inc.
- Inventors: Jian Shi; Yan Hu; Shuiqing Hu; Ji Ma; Chanmin Su
- Web page: https://patentgrep.com/patent/US20160258979A1

## 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

Methods and apparatuses are provided for automatically controlling and stabilizing aspects of a scanning probe microscope (SPM), such as an atomic force microscope (AFM), using Peak Force Tapping (PFT) Mode. In an embodiment, a controller automatically controls periodic motion of a probe relative to a sample in response to a substantially instantaneous force determined, and automatically controls a gain in a feedback loop. A gain control circuit automatically tunes a gain based on separation distances between a probe and a sample to facilitate stability. Accordingly, instability onset is quickly and accurately determined during scanning, thereby eliminating the need of expert user tuning of gains during operation.

## Claims

### Claim 1

A method for monitoring effectiveness a scanning probe microscope (SPM), the method comprising:
providing relative motion between a probe and a sample and controlling that motion using a feedback loop;
detecting an attractive force between the probe and the sample; and
comparing the attractive force to a predetermined threshold.

### Claim 2 (depends on 1)

The method of claim 1, wherein the attractive force substantially results from an adhesion force between the probe and the sample.

### Claim 3 (depends on 2)

The method of claim 2, wherein the adhesion force is determined according to a maximum adhesion force.

### Claim 4 (depends on 2)

The method of claim 2, wherein the adhesion force is determined according to an integration of a work of adhesion with respect to a departure point from and a return point to a non-interacting zero force baseline.

### Claim 5 (depends on 1)

The method of claim 1, wherein the attractive force substantially results from van der Waals forces.

### Claim 6 (depends on 5)

The method of claim 5, wherein the van der Waals forces are determined according to a slope with respect to a non-interacting zero force baseline.

### Claim 7

A method for monitoring tip health of a probe of a scanning probe microscope (SPM) during SPM operation, the method comprising:
providing relative motion between a probe and a sample and controlling the motion using peak force tapping (PFT) mode;
providing relative scanning motion between the probe and the sample so said controlling step is performed at multiple pixels along a scan line;
generating a force curve at each pixel; and
automatically determining tip health at each pixel in real time.

### Claim 8 (depends on 7)

The method of claim 7, further comprising detecting an attractive force between the probe and the sample; and
comparing the attractive force to a predetermined threshold.

### Claim 9 (depends on 8)

The method of claim 8, wherein the attractive force substantially results from an adhesion force between the probe and the sample.

### Claim 10 (depends on 9)

The method of claim 9, wherein the adhesion force is determined according to a maximum adhesion force.

### Claim 11 (depends on 9)

The method of claim 9, wherein the adhesion force is determined according to an integration of a work of adhesion with respect to a departure point from and a return point to a non-interacting zero force baseline.

### Claim 12 (depends on 8)

The method of claim 8, wherein the attractive force substantially results from van der Waals forces.

### Claim 13 (depends on 12)

The method of claim 12, wherein the van der Waals forces are determined according to a slope with respect to a non-interacting zero force baseline.

### Claim 14 (depends on 13)

The method of claim 13, wherein the determining step is performed at least every 300 microseconds.