Method and device for producing an image

• US 8,076,641 B2
• Filed: 06/22/2007
• Issued: 12/13/2011
• Est. Priority Date: 07/06/2006
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carlzeiss NTS GmbH
• Inventors: Sellmair, Josef
• Primary Examiner(s): Vanore, David A
• Application Number:
  US12/309,047
• Publication Number:
  US 20090314937A1
• Time in Patent Office: 1,635 Days
• Field of Search: 250/309, 250/310, 250/492.22, 250/492.3
• US Class Current: 250/310
• CPC Class Codes: H01J 2237/06341 Field emission
• CPC Class Codes: H01J 2237/24495 Signal processing, e.g. mixing of two or more signals
• CPC Class Codes: H01J 2237/2826 Calibration for object processing apparatus H01J2237/30433
• CPC Class Codes: H01J 2237/30455 Correction during exposure
• CPC Class Codes: H01J 37/073 Electron guns using field emission, photo emission, or secondary emission electron sources
• CPC Class Codes: H01J 37/244 Detectors; Associated components or circuits therefor
• CPC Class Codes: H01J 37/265 Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01J 37/3005 Observing the objects or the point of impact on the object
• CPC Class Codes: H01J 37/3045 Object or beam position registration

Abstract

The invention relates to a method and to a device (1) for producing an image of an object (5) by means of a particle beam. According to the method and in the device (1), the particle beam is scanned by the object (5). The aim of the invention is to provide a method and a device for producing an image of an object (5) by means of a particle beam that can be used with a cold field emitter (2) in such a manner that a good image quality is constantly ensured. Said aim is achieved by virtue of the fact that, according to the invention, when a radiation parameter is altered, the object (5) is rescanned preferably with the corrected parameter. The inventive device (1) comprises the corresponding means (4, 6, 7) therefor.

Claims

1. A method for producing an image of an object using a particle beam that is scanned over the object, comprising:

determining a parameter that is assigned to the particle beam;

determining whether a change has occurred in the parameter;

determining a location on the object at which the change occurred in the parameter;

returning the particle beam to the location; and

rescanning the particle beam over the object from the location onward.

2. The method as recited in claim 1, wherein the parameter is changed to a setpoint value.

3. The method as recited in claim 1, wherein the parameter is integrated over a specified period of time, and wherein the method further comprises:

determining whether a change has occurred in the parameter.

4. The method as recited in claim 1, wherein the particle beam is scanned over the object from a first point of a specified pattern to a second point of the specified pattern, and wherein, if determined that a change has occurred in the parameter, the particle beam is not returned during the scanning process until the particle beam has reached the second point of the specified pattern.

5. The method as recited in claim 4, wherein at least one of:

a row and a column is used as the specified pattern.

6. The method as recited in claim 1, wherein a current of the particle beam is determined as the parameter.

7. The method as recited in claim 1, wherein the particle beam is scanned over the object using a scanner which is controlled by an evaluation unit.

8. The method as recited in claim 7, wherein at least one of:

the parameter and the location is determined via the evaluation unit.

9. The method as recited in claim 1, wherein the particle beam is an electron beam, and wherein the electron beam is scanned over the object.

10. The method as recited in claim 1, wherein the particle beam is produced using at least one of:

a cold field emitter and a deposited field emitter.

11. The method as recited in claim 1, wherein a threshold value of the change in the parameter is settable.

12. A method for producing an image of an object using a particle beam that is scanned over the object, comprising:

determining a parameter that is assigned to the particle beam;

determining whether a change has occurred in the parameter;

determining a location on the object at which the change occurred in the parameter;

returning the particle beam to the location; and

rescanning the particle beam over the object from the location onward, wherein the particle beam is guided to at least one raster point, at which an integrating measurement is carried out, and wherein the particle beam is returned to the raster point if the raster point is the location at which the change occurred in the parameter.

13. A method for producing an image of an object using a particle beam that is scanned over the object, comprising:

determining a parameter that is assigned to the particle beam;

determining whether a change has occurred in the parameter;

determining a location on the object at which the change occurred in the parameter;

returning the particle beam to the location; and

rescanning the particle beam over the object from the location onward, wherein, when a change has occurred in the parameter, at least one of;

an image brightness and an image contrast is adjusted.

14. A device for producing an image of an object using a particle beam that is scanned over the object, comprising:

at least one particle beam generator for producing a particle beam;

at least one scanner for scanning the particle beam over the object;

at least one parameter determining device for determining a parameter that is assigned to the particle beam;

at least one change determining device for determining that a change has occurred in the parameter;

at least one location determining device for determining a location on the object at which the change occurred in the parameter; and

at least one returning device for returning the particle beam to the location.

15. The device as recited in claim 14, wherein a controller is provided for changing the parameter to a setpoint value.

16. The device as recited in claim 14, wherein the returning device for returning the particle beam is integrated in the scanner.

17. The device as recited in claim 14, wherein the returning device for returning the particle beam and the scanner are identical.

18. The device as recited in claim 14, wherein the parameter determining device for determining the parameter assigned to the particle beam determines the particle beam current.

19. The device as recited in claim 14, wherein the parameter determining device for determining the parameter assigned to the particle beam is at least one of:

located between the particle beam generator and the object and integrated in the particle beam generator.

20. The device as recited in claim 14, wherein the change determining device for determining that a change has occurred in the parameter is accommodated in the location determining device for determining the location.

21. The device as recited in claim 14, wherein the change determining device for determining that a change has occurred in the parameter and the location determining device for determining the location are identical.

22. The device as recited in claim 14, wherein at least two of:

the parameter determining device for determining the parameter, the change determining device for determining that a change has occurred in the parameter, the location determining device for determining the location on the object, and the returning device for returning the particle beam are connected to each other.

23. The device as recited in claim 15, wherein the controller for changing the parameter is connected to the particle beam generator.

24. The device as recited in claim 14, wherein at least one of:

the parameter determining device for determining the parameter, the change determining device for determining that a change has occurred in the parameter, and the location determining device for determining the location on the object is located in an evaluation unit.

25. The device as recited in claim 14, wherein the particle beam generator is at least one of an electron source, a cold field emitter, and a miniaturized cold field emitter.

26. The device as recited in claim 14, wherein the device is an electron beam device.

27. The device as recited in claim 14, further comprising:

a setting device for setting a threshold value with regard to the change in the parameter.

28. The device as recited in claim 14, further comprising:

a measuring device for performing an integrating measurement.

29. A device for producing an image of an object using a particle beam that is scanned over the object, comprising:

at least one particle beam generator for producing a particle beam;

at least one scanner for scanning the particle beam over the object;

at least one parameter determining device for determining a parameter that is assigned to the particle beam;

at least one change determining device for determining that a change has occurred in the parameter;

at least one location determining device for determining a location on the object at which the change occurred in the parameter;

at least one returning device for returning the particle beam to the location; and

an adjustment device for adjusting at least one of;

an image brightness and an image contrast.

30. An electron beam device for producing an image of an object using an electron beam that is scanned over the object, comprising:

at least one electron beam generator for producing an electron beam;

at least one objective lens for focusing the electron beam on the object;

at least one scanner for scanning the electron beam over the object;

at least one parameter determining device for determining a parameter that is assigned to the electron beam;

at least one change determining device for determining that a change has occurred in the parameter;

at least one location determining device for determining a location on the object at which the change occurred in the parameter; and

at least one returning device for returning the electron beam to the location.

31. The electron beam device as recited in claim 30, further comprising:

a controller for changing the parameter to a setpoint value.

32. A method for producing an image of an object using a particle beam that is scanned over the object, comprising:

determining a parameter that is assigned to the particle beam before the particle beam is scanned over the object;

determining whether a change has occurred in the parameter;

determining a location on the object at which the change occurred in the parameter;

returning the particle beam to the location if the change in the parameter exceeds a predefined threshold; and

rescanning the particle beam over the object from the location onward.