Maskless optical writer

• US 7,548,301 B2
• Filed: 01/24/2006
• Issued: 06/16/2009
• Est. Priority Date: 01/13/2004
• Status: Expired due to Fees

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Sewell, Harry
• Primary Examiner(s): NGUYEN, HUNG
• Application Number:
  US11/337,691
• Publication Number:
  US 20060119827A1
• Time in Patent Office: 1,239 Days
• Field of Search: 355/53, 355 67- 71, 430/5, 430/20, 430/30, 359/290, 359/245
• US Class Current: 355/67
• CPC Class Codes: A61B 6/4435 the source unit and the detector unit being coupled by a rigid structure
• 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
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

A maskless pattern generating system for use in lithographic processing includes a liquid crystal pixel array. The system generates a light beam and applies a voltage level to each pixel of the pixel array to modulate a polarization state of the light beam so as to create a pattern image. The voltage levels correspond to greyscale levels assigned to the pixels. The system can receive a control signal input based on pattern information that defines the pattern image. The setting of the individual voltage levels can allow the liquid crystal pixel array to act as a phase shift mask, can allow the pattern image to be shifted, and can allow the manipulation of a pattern image edge. This maskless pattern writing system acts as a light valve to control pattern imagery, on a pixel by pixel basis, for the purposes of direct writing patterns.

Claims

1. A method of generating a pattern for use in a maskless lithographic processing system using a pixel array of a liquid crystal programmable pattern generator having a plurality of pixels, comprising:

generating an individual voltage level for respective pixels of a pixels array of a liquid crystal pattern generator; and

applying the individual voltage level to the respective pixels of the pixel array to modulate a polarization state of a light beam interacting with the liquid crystal pattern generator so as to create a pattern image, wherein the individual voltage level corresponds to one of at least three different greyscale levels.

2. The method of claim 1, further comprising:

receiving a control signal input from a controller based on pattern information provided to the controller, the control signal input defining the pattern image.

3. The method of claim 1, further comprising:

polarizing the pattern image.

4. The method of claim 1, wherein the applying the individual voltage level comprises phase-shifting the pattern image by setting the individual voltage levels subsequent to one cycle of light.

5. The method of claim 1, wherein the applying the individual voltage level comprises shifting the pattern image by shifting settings of the individual voltage levels in one direction by the same number of pixel rows.

6. The method of claim 1, wherein the applying the individual voltage level comprises manipulating the edge of the pattern image by setting the individual voltage levels corresponding to individual pixels that are one of:

part of an edge of the pattern image; and

a pixel row beyond pixels that are part of the edge of the pattern image.

7. The method of claim 1, wherein the applying the individual voltage level to the respective pixels comprises applying one of:

a maximum voltage;

no voltage; and

a percentage of the maximum voltage.

8. The method of claim 1, further comprising:

reducing the pattern image with reduction optics for projection onto a substrate;

positioning the substrate relative to the reduction optics; and

projecting the pattern image onto the substrate.

9. The method of claim 8, wherein the reducing the pattern image comprises:

reflecting the light beam from the liquid crystal pattern generator through a polarizing beam splitter toward the reduction optics.

10. A maskless pattern generating system for use in a lithographic processing system, the maskless pattern system including a liquid crystal pixel array of a plurality of pixels and comprising:

means for generating an individual voltage level for respective pixels of a pixel array of the liquid crystal pattern generator; and

means for applying the individual voltage level to the respective pixels of the pixel array to modulate a polarization state of a light beam interacting with the liquid crystal pattern generator so as to create a pattern image, wherein the individual voltage level corresponds to one of at least three different greyscale levels.

11. The maskless pattern generating system of claim 10, further comprising:

means for receiving a control signal input from a controller based on pattern information provided to the controller, the control signal input defining the pattern image.

12. The maskless pattern generating system of claim 10, further comprising:

means for polarizing the pattern image.

13. The maskless pattern generating system of claim 10, wherein the means for applying the individual voltage level is operable to phase shift the pattern image by setting the individual voltage levels subsequent to one cycle of light.

14. The maskless pattern generating system of claim 10, wherein the means for applying the individual voltage level is operable to shift the pattern image by shifting the settings of the individual voltage levels in one direction by the same number of pixel rows.

15. The maskless pattern generating system of claim 10, wherein the means for applying the individual voltage level is operable to manipulate an edge of the pattern image by setting the individual voltage levels corresponding to individual pixels that are one of:

part of the edge of the pattern image; and

a pixel row beyond pixels that are part of the edge of the pattern image.

16. The maskless pattern generating system of claim 10, wherein the means for applying the individual voltage level to the respective pixels applies one of:

a maximum voltage;

no voltage; and

a percentage of the maximum voltage.

17. The maskless lithography system of claim 10, further comprising:

means for reducing the pattern image for projection onto a substrate;

means for positioning the substrate relative to the means for reducing the pattern image; and

means for projecting the pattern image onto the substrate.

18. A system for use in a lithographic processing system comprising:

a voltage generator configured to generate respective individual voltage levels; and

a liquid crystal pattern generator comprising a pixel array of respective pixels;

wherein the respective individual voltage levels are applied to the respective pixels of the pixel array to modulate a polarization state of a light beam interacting with the liquid crystal pattern generator so as to create a pattern image, and

wherein the respective individual voltage levels correspond to one of at least three different greyscale levels.

19. The system of claim 18, further comprising:

a controller configured to generate a control signal based on pattern information provided to the controller, the control signal defining the pattern image.

20. The system of claim 18, further comprising:

a polarizer configured to polarize the pattern image.

21. The system of claim 18, wherein the liquid pixel pattern generator is configured to phase-shift the pattern image by setting the respective individual voltage levels subsequent to one cycle of light.

22. The system of claim 18, wherein the liquid pixel pattern generator is configured to shift the pattern image based on shifting settings of the respective individual voltage levels in one direction by the same number of pixel rows.

23. The system of claim 18, wherein the liquid pixel pattern generator is configured to manipulate the edge of the pattern image based on setting the respective individual voltage levels corresponding to individual pixels that are one of:

part of an edge of the pattern image; and

a pixel row beyond pixels that are part of the edge of the pattern image.

24. The system of claim 18, wherein the respective individual voltage levels comprise:

a maximum voltage;

no voltage;

or

a percentage of the maximum voltage.