Altering pattern data based on measured optical element characteristics

• US 20070291240A1
• Filed: 06/19/2006
• Published: 12/20/2007
• Est. Priority Date: 06/19/2006
• Status: Active Grant

• Current Assignee: ASML Holding NV, ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Holding NV
• Inventors: Hintersteiner, Jason D., Cebuhar, Wenceslao A., Tinnemans, Patricius Aloysius Jacobus
• Granted Patent: US 7,936,445 B2
• Time in Patent Office: Days
• US Class Current: 355/52
• CPC Class Codes: G03B 27/42 for automatic sequential copying of the same original G03B27/34, G03B27/53 take precedence
• CPC Class Codes: G03B 27/68 Introducing or correcting distortion, e.g. in connection with oblique projection
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices
• CPC Class Codes: G03F 7/706 Aberration measurement

Abstract

A system and method are used to compensate for distortions or aberrations in an image formed in a projection system. Pattern data is generated corresponding to features to be formed on a substrate. At least one of aberrations and distortions of a projection optical system are measured. The pattern data is altered based on the measuring step. The altered pattern data is transmitted to a patterning device to control individually controllable elements coupled to the patterning device. Non uniformities in one or both of a field and pupil of an illumination system can also be measured and used to alter the pattern data.

Claims

1. A method, comprising:

(a) generating pattern data corresponding to features to be formed on a substrate;

(b) measuring at least one of aberrations and distortions of a projection system;

(c) altering the pattern data based on measuring step (b); and

(d) transmitting the altered pattern data to a patterning device to control individually controllable elements coupled to the patterning device.

2. The method of claim 1, wherein:

step (b) comprises measuring the at least one of aberrations and distortions of the projection system; and

step (c) comprises altering the pattern data to form an image free from the at least one of measured aberrations and distortions.

3. The method of claim 1, wherein step (d) comprises using a digitally controlled array of micro-mirrors having multiple mirror positions as the individually controllable elements.

4. The method of claim 1, wherein an amplitude and a phase of the image is controlled through control of the patterning device.

5. The method of claim 1, wherein step (b) further comprises measuring at least one of barometric pressure and temperature of the projection system.

6. The method of claim 1, wherein step (c) further comprises compensating for high frequency ones of the at least one of aberrations and distortions caused by a surface imperfection on one or more optical elements in the projection system.

7. The method of claim 1, wherein steps (b)-(d) are performed periodically.

8. The method of claim 1, wherein steps (b)-(d) are performed continuously during the patterning of the substrate in real time.

9. The method of claim 1, wherein steps (b)-(d) compensate for at least one of dynamic and static ones of the at least one of aberrations and distortions.

10. The method of claim 1, wherein:

step (b) comprises measuring the at least one of aberrations and distortions at an image plane of the projection optical system and transforming measured values to a pupil plane of the projection system; and

step (c) comprises altering the pattern data to form an image at the pupil plane and the image plane free from the at least one of measured aberrations and distortions.

11. The method of claim 1, wherein step (b) comprises combining multiple measurements taken from different portions of an image plane.

12. The method of claim 1, further comprising before step (d):

measuring imperfections in a pupil of an illumination system that provides illumination radiation to the patterning device; and

altering the pattern data based on the illumination system measuring step.

13. The method of claim 1, further comprising before step (d):

measuring non-uniformities in a field of an illumination system that provides illumination radiation to the patterning device; and

altering the pattern data based on the illumination system measuring step.

14. The method of claim 1, further comprising before step (d):

measuring a speckle pattern of an illumination system that provides illumination radiation to the patterning device; and

altering the pattern data based on the illumination system measuring step.

15. The method of claim 1, further comprising before step (d):

measuring non-uniformities in a field and imperfections in a pupil of an illumination system that provides illumination radiation to the patterning device; and

altering the pattern data based on the illumination system measuring step.

32. The method of claim 1, wherein:

step (b) comprises measuring the at least one of aberrations and distortions at an image plane of the projection optical system; and

step (c) comprises altering the pattern data to form an image at the image plane free from the at least one of measured aberrations and distortion.

16. A lithographic system, comprising:

an illumination system that processes a beam of radiation;

a patterning device including a controller and an array of individually controllable elements, the controller being configured to control the array of individually controllable elements based on received pattern data to pattern the beam of radiation;

a projection system that is used to project the patterned beam onto a target portion of a substrate; and

a measuring system that is configured to measure at least one of aberrations or distortions of the projection system,

wherein the controller uses the measured at least one of aberrations or distortions to alter the pattern data.

17. The lithography system of claim 16, wherein:

the measuring system is configured to measure the at least one of aberrations and distortions of the projection system; and

the controller alters the pattern data to form an image at the pupil plane free from the at least one of measured aberrations and distortions.

18. The lithography system of claim 16, wherein the array of individually controllable elements comprises a digitally controlled array of micro-mirrors having multiple mirror positions.

19. The lithography system of claim 16, wherein the controller controls the patterning device to adjust an amplitude and a phase of the patterned beam.

20. The lithography system of claim 16, wherein:

the measuring system is configured to measure at least one of barometric pressure and temperature of the projection system; and

the controller is configured to use the at least one of barometric pressure and temperature to alter the pattern data.

21. The lithography system of claim 16, wherein the controller compensates for high frequency ones of the at least one of aberrations and distortions caused by a surface imperfection on one or more optical elements in the projection system.

22. The lithography system of claim 16, wherein the measuring system and the controller periodically alter the pattern data.

23. The lithography system of claim 16, wherein the measuring system and the controller continuously alter the pattern data in real time.

24. The lithography system of claim 16, wherein the measuring system and the controller compensate for at least one of dynamic and static ones of the at least one of aberrations and distortions.

25. The lithography system of claim 16, wherein:

the measuring system measures the at least one of aberrations and distortions at an image plane of the projection system and transforms measured values to a pupil plane of the projection system; and

the controller alters the pattern data to form an image at the pupil plane and the image plane free from the at least one of measured aberrations and distortions.

26. The lithography system of claim 16, wherein the measuring systems combines multiple measurements taken from different points of a measuring plane.

27. The lithography system of claim 26, wherein the measuring system comprises a plurality of measuring devices, each corresponding to one of the different portions of the measuring plane.

28. The lithography system of claim 16, wherein:

the measuring system measures imperfections in a pupil of an illumination system that provides illumination radiation to the patterning device; and

the controller alters the pattern data based on the illumination system measuring step.

29. The lithography system of claim 16, wherein:

the measuring system measures non-uniformities in a field of an illumination system that provides illumination radiation to the patterning device; and

the controller alters the pattern data based on the measured field of the illumination system.

30. The lithography system of claim 16, wherein:

the measuring system measures a speckle profile from an illumination system that provides illumination radiation to the patterning device; and

the controller alters the pattern data based on the measured speckle profile of the illumination system.

31. The lithography system of claim 16, wherein:

the measuring system measures non-uniformities in a field and imperfections in a pupil of an illumination system that provides illumination radiation to the patterning device; and

the controller alters the pattern data based on the measured field and the measured pupil of the illumination system.

33. The lithography system of claim 16, wherein:

the measuring system measures the at least one of aberrations and distortions at an image plane of the projection system; and

the controller alters the pattern data to form an image at the image plane free from at least one of measured aberration and distortions.