Fast-scanning SPM and method of operating same

• US 7,770,231 B2
• Filed: 08/02/2007
• Issued: 08/03/2010
• Est. Priority Date: 08/02/2007
• Status: Active Grant

• Current Assignee: Bruker Nano, Inc. (Bruker Corporation)
• Original Assignee: Veeco Instruments Incorporated
• Inventors: Prater, Craig, Shi, Jian, Markakis, Jeffrey M., Phan, Nghi, Kindt, Johannes H., Cusworth, Craig, Fan, Wenjun, Su, Chanmin, Nagle, Steven F.
• Primary Examiner(s): Souw; Bernard E
• Assistant Examiner(s): Logie; Michael J
• Application Number:
  US11/832,881
• Publication Number:
  US 20090032706A1
• Time in Patent Office: 1,097 Days
• Field of Search: 250/306, 250/307, 850/1, 850/3, 850/5, 850/6, 850/21, 850/33, 850/52, 850/53, 850/56, 850/60, 850/61, 850/62, 850/63, 731/05
• US Class Current: 850/6
• CPC Class Codes: G01Q 10/04 Fine scanning or positioning
• CPC Class Codes: G01Q 10/065 Feedback mechanisms, i.e. wherein the signal for driving the probe is modified by a signal coming from the probe itself
• CPC Class Codes: G01Q 20/02 by optical means
• CPC Class Codes: G01Q 60/38 Probes, their manufacture, or their related instrumentation, e.g. holders

Abstract

A method and apparatus are provided that have the capability of rapidly scanning a large sample of arbitrary characteristics under force control feedback so has to obtain a high resolution image. The method includes generating relative scanning movement between a probe of the SPM and a sample to scan the probe through a scan range of at least 4 microns at a rate of at least 30 lines/sec and controlling probe-sample interaction with a force control slew rate of at least 1 mm/sec. A preferred SPM capable of achieving these results has a force controller having a force control bandwidth of at least closed loop bandwidth of at least 10 kHz.

Claims

1. A method of operating a scanning probe microscope (SPM) comprising:

actuating a piezoelectric actuator assembly to move a probe of the SPM to scan the probe past a sample through a scan range of at least 4 microns at a rate of at least 30 lines/sec and moving the probe in z a direction under control of a piezoelectric z actuator;

measuring motion of the probe using a sensing light beam and a detector;

moving at least one lens so that the sensing beam at least substantially follows the scanning motion of the probe; and

controlling probe-sample interaction with a force control slew rate of at least 1 mm/sec; and

at least one of storing, transmitting, and displaying at least one of the measurement and information derived from the measurement.

2. The method of claim 1, wherein the force control slew rate is at least 4 mm/sec.

3. The method of claim 1, wherein the force control slew rate is at least 7 mm /sec.

4. The method of claim 1, wherein the scanning is performed at a rate of at least 100 lines/sec.

5. The method of claim 4, wherein the scanning is performed at a rate of at least 1000 lines/sec.

6. The method of claim 1, wherein the scanning comprises scanning through a scan range of at least 10 μ

m.

7. The method of claim 6, wherein the scanning comprises scanning through a scan range of at least 20 μ

m.

8. The method of claim 1, wherein the scanning is performed with a force control bandwidth of at least 10 kHz.

9. The method of claim 1, wherein the generating step also causes the sample to move in the xy plane in a nested control relationship with probe movement.

10. The method of claim 1, wherein the controlling step further comprises moving the sample in the z direction in a nested control relationship with probe movement.

11. The method as reciting in claim 1, further comprising oscillating the probe.

12. The method of claim 11, wherein the controlling step comprises maintaining a probe oscillational amplitude at least generally constant.

13. The method of claim 11, wherein the controlling step comprises maintaining a probe oscillational phase at least generally constant.

14. The method of claim 1, wherein the sample is one of a patterned wafer, a biological sample, a data storage device component, a polymer, and a thin film.

15. A method of operating a scanning probe microscope (SPM) comprising:

actuating a piezoelectric actuator assembly to move a probe of the SPM past a sample to scan the probe through a scan range of at least 4 microns at a rate of at least 30 lines/sec and moving the probe in a z direction under control of a piezoelectric z actuator;

measuring motion of the probe using a sensing light beam and a detector;

moving at least one lens so that the sensing beam at least substantially follows the scanning motion of the probe; and

controlling probe-sample interaction with a force control bandwidth of at least 10 kHz; and

at least one of storing, transmitting, and displaying at least one of the measurement and information derived from the measurement.

16. The method of claim 15, wherein the scanning is performed with a force control bandwidth of at least 20 kHz.

17. The method of claim 15, wherein the scanning is performed with a force control bandwidth of at least 50 kHz.

18. The method of claim 15, further comprising controlling probe-sample interaction with a force control slew rate of at least 1 mm/sec.

19. The method of claim 18, wherein the force control slew rate is at least 4 mm /sec.

20. A scanning probe microscope (SPM) comprising:

a piezoelectric actuator assembly that moves probe of the SPM past a sample to scan the probe through a scan range of at least 4 microns at a rate of at least 30 lines/sec;

a piezoelectric actuator that moves the probe in a z direction;

means for measuring motion of the probe using a sensing light beam and a detector;

means for moving at least one lens so that the sensing beam at least substantially follows the scanning motion of the probe; and

means for controlling probe-sample interaction with a force control slew rate of at least 1 mm/sec.

21. The SPM of claim 20, further comprising means for at least one of storing, transmitting, and displaying at least one of the measurement and information derived from the measurement.

22. A scanning probe microscope (SPM) comprising:

a scanner including

     1) a piezoelectric actuator assembly that moves a probe of the SPM past a sample to scan the probe through a scan range of at least 4 microns at a rate of at least 30 lines/sec and

     2) a piezoelectric actuator that moves the probe in a z direction;

a sensing light beam and detector that measure motion of the probe;

at least one lens disposed between the scanning light beam and the sample, the lens being movable to cause the sensing beam to at least substantially follow the scanning motion of the probe; and

a controller that controls probe-sample interaction with a force control slew rate of at least 1 mm/sec.

23. The SPM of claim 22, further comprising a device that at least one of stores, transmits, and displays at least one of the measurement and information derived from the measurement.

24. The SPM of claim 22, wherein the probe has a force detection bandwidth greater than 30 kHz and applies a force to the sample of less than 10 nN when activated in oscillation mode.

25. The SPM of claim 22, wherein the probe has a force detection bandwidth greater than 100 kHz and applies a force to the sample of less than 5 nN when activated in oscillation mode.

26. The SPM of claim 22, wherein the probe has a step response time of about 10 μ

s.