Illumination system

• US 20070127005A1
• Filed: 12/02/2005
• Published: 06/07/2007
• Est. Priority Date: 12/02/2005
• Status: Abandoned Application

• Current Assignee: ASML Holding NV, ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Holding NV, ASML Netherlands BV (ASML Holding NV)
• Inventors: Visser, Huibert, Ryzhikov, Lev, Joobeur, Adel, Shmarev, Yevgeniy Konstantinovich, Coston, Scott, Klinkhamer, Jacob, VINK, HENRI JOHANNES
• Application Number:
  US11/292,275
• Publication Number:
  US 20070127005A1
• Time in Patent Office: Days
• US Class Current: 355/71
• CPC Class Codes: G02B 27/0905 Dividing and/or superposing multiple light beams
• CPC Class Codes: G03F 7/70075 Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection
• CPC Class Codes: G03F 7/70583 Speckle reduction, e.g. coherence control or amplitude/wavefront splitting

Abstract

A system and method are used to substantially homogenizing and removing at least some coherence from a beam of light.

Claims

1. An optical apparatus, comprising:

a coherence remover having a plurality of channels; and

a homogenizer that converts a beam of light into a plurality of beams of light, such that each respective ones of the plurality of beams of light passes through a respective one of the plurality of channels of the coherence remover.

2. The optical apparatus of claim 1, further comprising:

an optical element located between the homogenizer and the coherence remover, the optical element being arranged to couple the plurality of beams of light output from the homogenizer into the respective channels of the coherence remover.

3. The optical apparatus of claim 1, wherein the coherence remover comprises:

a plurality of transmissive optical elements, the optical elements having different path lengths, such that respective ones of the plurality of light beams that are initially coherent with one another when they enter the coherence remover are no longer coherent with one another when they exit the coherence remover.

4. The optical apparatus of claim 3, wherein the transmissive optical elements are arranged in a stepped series.

5. The optical apparatus of claim 3, wherein the transmissive optical elements are arranged in a two dimensional array.

6. The optical apparatus of claim 1, further comprising:

a convex lens arranged to focus the beams of light, such that the beams of light are combined with one another to form a single beam of light.

7. The optical apparatus of claim 6, wherein:

the optical apparatus comprises part of a lithographic apparatus;

the lithographic apparatus comprises a patterning array that comprises an array of individually controllable elements; and

the single beam or a plurality of beams generated from the single beam is directed to the patterning array.

8. The optical apparatus of claim 1, wherein:

the optical apparatus comprises part of a lithographic apparatus; and

the lithographic apparatus comprises a patterning array that comprises an array of individually controllable elements.

9. The optical apparatus of claim 1, wherein the homogenizer comprises at least one homogenizer plate.

10. The optical apparatus of claim 1, wherein the homogenizer comprises a pair of parallel homogenizer plates.

11. The optical apparatus of claim 1, wherein the homogenizer comprises a pair of homogenizer plates which are angled relative to one another.

12. The optical apparatus of claim 11, wherein the homogenizer plates are rotatably mounted such that the angular orientation of the homogenizer plates is adjustable.

13. A lithographic apparatus, comprising:

an illumination system that conditions a radiation beam and comprises a coherence remover;

an array of individually controllable elements that modulate the radiation beam; and

a projection system that projects the modulated beam onto a target portion of a substrate.

14. The lithographic apparatus of claim 13, wherein the illumination system forms a plurality of the beams and the coherence remover comprises:

a plurality of channels configured to receive respective ones of the plurality of beams.

15. The lithographic apparatus of claim 13, wherein the coherence remover comprises:

a plurality of transmissive optical elements having different optical lengths.

16. The lithographic apparatus of claim 15, wherein the transmissive optical elements are arranged in a stepped series.

17. The lithographic apparatus of claim 15, wherein the transmissive optical elements are arranged in a two dimensional array.

18. The lithographic apparatus of claim 17, wherein the lithographic apparatus further comprises:

a homogenizer that converts the radiation beam into a plurality of radiation beams;

wherein the coherence remover comprises a plurality of channels that pass respective ones of the plurality of beams of radiation.

19. The lithographic apparatus according to claim 13, wherein the projection system comprises:

an array of lenses that are arranged to direct individual beams of light onto the substrate.

20. A lithographic apparatus for manufacturing flat panel displays, comprising:

an illumination system that conditions a radiation beam and comprises a coherence remover;

a mask or an array of individually controllable elements capable of modulating the radiation beam; and

a projection system configured to project the modulated radiation beam onto a target portion of a substrate.

21. The lithographic apparatus of claim 20, wherein the coherence remover comprises a plurality of transmissive optical elements having different optical lengths.

22. The lithographic apparatus of claim 21, wherein the transmissive optical elements are arranged in a stepped series.

23. The lithographic apparatus of claim 21, wherein the transmissive optical elements are arranged in a two dimensional array.

24. A homogenizer, comprising:

first and second homogenizer plates that are angled relative to one another.

25. The homogenizer of claim 24, wherein the homogenizer plates are rotatably mounted, such that the angular orientation of the homogenizer plates is adjustable.