Optical profilometer combined with stylus probe measurement device

• US 5,955,661 A
• Filed: 01/06/1997
• Issued: 09/21/1999
• Est. Priority Date: 01/06/1997
• Status: Expired due to Term

• Current Assignee: Tencor Instruments (KLA Corporation)
• Original Assignee: KLA-Tencor Corporation
• Inventors: Weber, Michael, Samsavar, Amin, Kuhn, William P., McWaid, Thomas, Parks, Robert E.
• Primary Examiner(s): LARKIN, DANIEL SEAN
• Application Number:
  US08/779,087
• Time in Patent Office: 988 Days
• Field of Search: 73/105, 750/306, 750/307
• US Class Current: 73/105
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G01B 21/04 by measuring coordinates of points
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G01Q 30/025 Optical microscopes coupled with SPM
• CPC Class Codes: Y10S 977/869 Optical microscope

Abstract

An optical profilometer and a stylus probe measuring device used in the same instrument have the advantage that these two sensors can be quickly switched between each other. This can be an advantage when used to measure samples, since the optical profilometer can be used until a sample is found to be outside of the desired tolerances. Afterwards, the stylus probe measuring device can be used to accurately determine the profile data. This is an advantage because an optical profilometer is relatively quick, and the stylus probe measuring device is relatively accurate. Additionally, since the optical profilometer and stylus probe device are in the same instrument, the X and Y positions of these devices can be interrelated accurately. This allows images to be produced where the positions on the images can be easily correlated. For example, measurement cursors in sensor data displays can correlated by the positional offset information.

Claims

1. An instrument for profiling a sample, comprising:

a stylus probe measuring device;

an optical profilometer that determines height information about a surface of the sample;

positioning means for positioning the stylus probe measuring device and the optical profilometer with respect to the sample; and

a controller adapted to control the positioning means.

2. The instrument of claim 1, wherein the stylus probe measuring device comprises a probe adapted to be positioned at or near the sample surface.

3. The instrument of claim 2, wherein the stylus probe measuring device is a stylus profilometer.

4. The instrument of claim 3, wherein the stylus profilometer comprises:

a stylus arm having a stylus tip; and

a capacitance gauge, a linear voltage differential transformer sensor, or a light intensity proximity sensor.

5. The instrument of claim 1, wherein the stylus probe measuring device comprises a scanning probe microscope.

6. The instrument of claim 5, wherein the stylus probe measuring device comprises an atomic force microscope.

7. The instrument of claim 1, wherein the controller is adapted to calibrate profile data from the optical profilometer using data from the stylus probe measuring device.

8. The instrument of claim 1, wherein the optical profilometer is an optical interferometer.

9. The instrument of claim 8, wherein the optical interferometer is a Nomorski optical interferometer.

10. The instrument of claim 1, wherein the stylus probe measuring device has a known positional relation to the optical profilometer.

11. The instrument of claim 10, wherein the controller is adapted to calibrate the XY offsets of the optical profilometer with respect to the stylus probe measuring device.

12. The instrument of claim 10, wherein the stylus probe measuring device has a fixed position with respect to the optical profilometer.

13. The instrument of claim 10, wherein the stylus probe measuring device has a movable position with respect to the optical profilometer.

14. The instrument of claim 1, wherein the positioning means includes an XY translator to hold the sample.

15. The instrument of claim 1, wherein the positioning means includes a Z translator attached to a sensor head containing the stylus probe measuring device and optical profilometer.

16. The instrument of claim 1, wherein the positioning means includes an XY translator attached to the stylus probe measuring device.

17. The instrument of claim 16, wherein the optical profilometer is not attached to the XY translator.

18. The instrument of claim 17, wherein the XY translator has a home position in which the optical profilometer has a known positional relation in an X and Y direction to the stylus probe measuring device.

19. The instrument of claim 1, wherein the positioning means includes a Z translator attached to the optical profilometer but not the stylus probe measuring device.

20. The instrument of claim 1, further comprising a display means for displaying profile data.

21. The instrument of claim 20, wherein the controller is further adapted to control the display of the profile data, the controller being adapted to produce a first display for the optical device data and a second display for the stylus probe data, wherein the controller is being adapted to display a cursor on one of the displays so that it corresponds to a position of a cursor on another of the displays.

22. The instrument of claim 21, wherein the controller is adapted to calibrate the XY offsets of the optical profilometer with respect to the stylus probe measuring device to increase the accuracy of the cursor positioning.

23. A method of operating a sensing instrument comprising:

providing an object;

using an optical profilometer to position a stylus probe measuring device on the object;

obtaining data about the object using stylus probe measuring device; and

using the stylus probe measuring device data to calibrate the X and Y position offset between the optical profilometer and the stylus probe measuring device.

24. The method of claim 23, wherein the providing step comprises providing an object with a raised edge.

25. The method of claim 24, wherein the stylus data obtaining step includes sweeping the stylus probe measuring device toward the raised edge so that an offset along one axis is determinable from an indication of the raised edge.

26. The method of claim 25, wherein the test object includes a triangle-shaped portion with the raised edge and wherein the length of a sweep across the triangle determined by the stylus probe measurement device allows for the determination of the offset along another axis.

27. A method of operating a sensing instrument comprising:

providing a test object;

using an optical device to position a scanning probe microscope on the test object;

obtaining data about the test object using a scanning probe microscope; and

using the scanning probe microscope data to calibrate the X and Y position offset between the optical device and the scanning probe microscope, wherein the providing step comprises providing a test object with a raised edge and wherein the scanning probe microscope data obtaining step includes sweeping the scanning probe microscope towards the raised edge so that an offset along one axis is determinable from an indication of the raised edge.

28. The method of claim 27, wherein the test object includes a triangle-shaped portion with the raised edge and wherein the length of a sweep across the triangle determined by the scanning probe microscope allows for the determination of the offset along another axis.

29. A method of operating a sensing instrument comprising:

obtaining profile data about a sample using an optical profilometer; and

obtaining profile data about the sample using a stylus probe measuring device;

wherein the two obtaining steps are done without removing the sample from the instrument.

30. The method of claim 29, wherein the stylus probe measuring device data is used to calibrate the height profile data of the optical profilometer.

31. The method of claim 29, wherein the stylus profile measuring step is done after the profile determined by the optical profilometer is outside a predetermined tolerance, the stylus profile measuring step producing a more accurate determination of the profile.

32. The method of claim 29, wherein the sample includes laser bumps.

33. A method of operating a sensing instrument comprising:

providing an object;

using an optical profilometer to locate a position on an object;

positioning a stylus probe measuring device at the position; and

obtaining profile information concerning the position using the stylus probe measuring device.

34. The method of claim 33, wherein the object has a pole tip recession at the position.

35. The method of claim 34, wherein the obtaining step includes obtaining information about the texture of the pole tip recession.

36. The method of claim 33, wherein data from the optical device is displayed on a display means.

37. A method of operating a sensing instrument comprising:

providing an instrument having at least two sensors;

measuring an object with one of the sensors;

moving another of the sensors to a measuring location using positional offset information;

measuring the object with the other of the sensors; and

producing displays of the measured data, measurement cursors in the displays being correlated by the positional offset information.

38. The method of claim 37, further comprising the step of determining the positional offset information using the at least two sensors.

39. The method of claim 37, wherein the providing step is such that the at least two sensors include an optical profilometer and a stylus probe measuring device.