Method for high precision printing of patterns

• US 6,833,854 B1
• Filed: 06/12/2003
• Issued: 12/21/2004
• Est. Priority Date: 06/12/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: Micronic Laser Systems AB (Mycronic AB)
• Inventors: Sandström, Torbjörn
• Primary Examiner(s): Wells, Nikita
• Application Number:
  US10/460,765
• Publication Number:
  US 20040251430A1
• Time in Patent Office: 558 Days
• Field of Search: 359/298, 359/308, 359/459, 347/239, 347/255, 250/461.1, 250/504.R, 250/365
• US Class Current: 347/239
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process
• 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

Abstract

An aspect of the present invention includes a method to print pattern with improved edge acuity. In one embodiment a method for printing fine patterns comprising the actions of: providing an SLM and providing a pixel layout pattern with different categories of modulating elements, the categories differing in the phase of the complex amplitude. Other aspects of the present invention are reflected in the detailed description, figures and claims.

Claims

1. A method for printing fine patterns with high precision, comprising the actions of:

providing an SLM having an array of modulator elements,

providing an electromagnetic radiation source to illuminate said SLM with partially coherent illumination with a coherence length that is larger than half the pitch of the modulating elements in the SLM,

creating a negative complex amplitude with at least one modulator element.

2. The method according to claim 1, wherein said radiation source is a pulsed laser source.

3. The method according to claim 1, wherein said electromagnetic radiation source having a wavelength in the region of UV, EUV, DUV, VUV.

4. The method according to claim 1, wherein said modulator elements are operated an analog mode.

5. The method according to claim 1, wherein said SLM is a reflective SLM.

6. The method according to claim 1, wherein said negative complex amplitude is more negative than −

0.218.

7. The method according to claim 1, wherein said negative complex amplitude is more negative than −

0.5.

8. A method for printing fine patterns, comprising the actions of:

providing an SLM,

providing a data path including a rasterizer,

rasterizing an input pattern to a grayscale bitmap,

providing an edge-sharpening filter operating on the bitmap.

9. The method according to claim 8, wherein said SLM is operated in an analog mode.

10. The method according to claim 8, wherein said pattern is printed using a multipass writing strategy.

11. The method according to claim 8, wherein said edge sharpening filter is a convolution filter.

12. The method according to claim 8, wherein said edge sharpening filter is a rule based filter.

13. A method for printing fine patterns comprising the actions of

providing an SLM and a partially coherent optical system,

providing a data path including a rasterizer,

rasterizing an input pattern to a grayscale bitmap,

providing an edge-sharpening filter operating on the bitmap,

wherein said edge-sharpening filter producing pixels with negative complex amplitude.

14. The method according to claim 13, wherein said SLM is operated in an analog mode.

15. The method according to claim 13, wherein said pattern is printed using multipass writing strategy.

16. The method according to claim 13, wherein said edge sharpening filter is a convolution filter.

17. The method according to claim 13, wherein said edge sharpening filter is a rule based filter.

18. A method for printing fine pattern comprising the actions of:

providing an SLM,

providing a partially coherent optical system,

providing pixels with less reflection close to the axis.

19. The method according to claim 18, wherein said pixels have less reflecting area close to the axis than further away.

20. The method according to claim 18, wherein said pixels are essentially rectangular and provided with anti-reflective coating close to the axis.

21. The method according to claim 18, wherein said pixels are essentially rectangular and provided with radiation scattering elements close to the axis.

22. A method for printing fine pattern comprising the actions of:

providing an SLM with an array of reflecting elements,

providing a surface profile for at least one reflecting element,

said surface profile having area elements with at least two heights.

23. The method according to claim 22, wherein said area elements are 180 apart for a wavelength chosen to print said pattern.

25. The method according to claim 23, wherein said bitmaps are combined into a single writing pass.

26. The method according to claim 23, wherein said bitmaps are combined into a plurality of writing passes.

27. The method according to claim 23, wherein at least one filter is a low-pass characteristics.

28. The method according to claim 23, wherein at least one filter is a high-pass characteristics.

29. The method according to claim 23, wherein said filters act differently in an X direction of the pattern and an Y direction of the pattern.

30. The method according to claim 23, wherein in a multipass writing strategy the optical settings are different for the different filters.

31. The method according to claim 27, wherein in a multipass writing strategy the optical settings are different for the different filters.

32. The method according to claim 28, wherein in a multipass writing strategy the optical settings are different for the different filters.

24. A method for printing fine patterns comprising the actions of:

providing an SLM,

providing a bitmap representing the input data,

separating said bitmap into two bitmaps,

filtering the two bitmaps using different filters,

combining the two bitmaps to expose the image.

33. A method for printing fine patterns comprising the actions of:

detecting edges in the bitmap,

characterizing the steepness of the transition of the edges,

making digital edge enhancements based on said steepness.

34. The method according to claim 33, wherein said input data is having at least two-valued layers.

35. The method according to claim 33, wherein said input data having features with different complex amplitudes.

36. The method according to claim 33, further comprising the action of:

rasterizing said features to multiple bitmaps and combining said bitmaps to drive the SLM.

37. A method for printing fine patterns comprising the actions of:

providing an SLM having analog function with a range from positive to negative complex amplitude reflection,

providing a data path,

providing input data describing a pattern having extended areas with at least three complex amplitude values and edges between them,

converting said data input to a bitmap of pixel values that correspond to both negative and positive complex amplitude.

38. The method according to claim 37, further comprising the action of:

rasterizing each two-valued layer bitmap and combining said bitmaps to drive the SLM.

39. A method for printing fine patterns comprising the actions of:

providing an SLM,

providing a pixel layout pattern with different categories of modulating elements, the categories differing in the phase of the complex amplitude.

40. The method according to claim 39, wherein said categories are two categories, a first with phase 0 and a second with a 180 degrees phase.

41. The method according to claim 39, wherein said categories are three categories, a first with a phase 0, a second with a phase 120, and a third with a phase 240 degrees.

42. The method according to claim 39, wherein said categories are four categories a first with phase 0, a second with phase 90, a third with phase 180, and a fourth with phase 270 degrees.