Thin Film Continuous Spatially Modulated Grey Attenuators and Filters

• US 20090122289A1
• Filed: 11/05/2008
• Published: 05/14/2009
• Est. Priority Date: 11/13/2007
• Status: Active Grant

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Wilklow, Ronald A., Ryzhikov, Lev, VLADIMIRSKY, Yuli
• Granted Patent: US 8,558,988 B2
• Time in Patent Office: Days
• US Class Current: 355/67
• CPC Class Codes: G03B 27/54 Lamp housings; Illuminating means
• CPC Class Codes: G03F 7/70191 Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like

Abstract

A system and method for use of a lithography apparatus having a substrate and an absorbing film formed on the substrate. A thickness of the absorbing film is spatially modulated across at least a part of the substrate to reduce a non-uniform intensity of a radiation beam transmitted through the substrate.

Claims

1. A lithography apparatus, comprising:

a substrate; and

an absorbing film formed on the substrate;

wherein a thickness of the absorbing film is spatially modulated across at least a part of the substrate to reduce a non-uniform intensity of a radiation beam transmitted through the substrate.

2. The apparatus of claim 1, wherein the thickness of the absorbing film is non-curvilinear across at least a part of the substrate.

3. The apparatus of claim 1, wherein the absorbing film comprises a material having an extinction coefficient from about 10⁻

6 to about 0.23.

4. The apparatus of claim 1, wherein the absorbing film comprises silicon oxy-nitride.

5. The apparatus of claim 4, wherein the silicon oxy-nitride comprises zero percent nitrogen to about twenty percent nitrogen.

6. The apparatus of claim 1, further comprising a wavefront compensator to compensate for a refractive effect of the absorbing film, wherein the wavefront compensator is formed on the substrate.

7. The apparatus of claim 6, wherein the wavefront compensator comprises silicon oxide.

8. The apparatus of claim 6, wherein the wavefront compensator has a thickness that is spatially modulated substantially complementary to the absorbing film thickness.

9. The apparatus of claim 1, wherein the substrate has a plano surface.

10. The apparatus of claim 1, wherein the substrate has a non-plano surface.

11. A lithography apparatus, comprising:

an illumination system configured to condition a beam of radiation;

a patterning device configured to pattern the beam of radiation;

a projection system configured to project the patterned beam onto a target area of a workpiece; and

an attenuator to condition the beam of radiation including

a substrate, and

an absorbing film located on the substrate,

wherein a thickness of the absorbing film is spatially modulated across at least a part of the substrate to reduce a non-uniform intensity of the radiation beam.

12. The apparatus of claim 11, wherein the beam of radiation has a wavelength of substantially 193 nanometers.

13. The apparatus of claim 11, wherein the absorbing film has a non-curvilinear thickness across at least a part of the substrate.

14. The apparatus of claim 11, wherein the absorbing film comprises a material having an extinction coefficient from about 10⁻

6 to about 0.23.

15. The apparatus of claim 11, wherein the absorbing film comprises silicon oxy-nitride.

16. The apparatus of claim 15, wherein the silicon oxy-nitride comprises from zero percent nitrogen to about twenty percent nitrogen.

17. The apparatus of claim 11, wherein the attenuator further comprises a wavefront compensator to compensate for a refractive effect of the absorbing film, wherein the wavefront compensator is formed on the substrate.

18. The apparatus of claim 17, wherein the wavefront compensator comprises silicon oxide.

19. The apparatus of claim 17, wherein the wavefront compensator has a thickness that is spatially modulated substantially complementary to the absorbing film thickness.

20. The apparatus of claim 11, wherein the substrate has a plano surface.

21. The apparatus of claim 11, wherein the substrate has a non-plano surface.

22. A method, comprising:

generating a radiation beam; and

transmitting the radiation beam through an absorbing film located on a substrate, wherein the absorbing film has a thickness that is spatially modulated across at least a part of the substrate to reduce a non-uniform intensity of the radiation beam.

23. The method of claim 22, further comprising transmitting the radiation beam through a wavefront compensator located on the substrate to reduce wavefront non-uniformity of the radiation beam.

24. The method of claim 22, further comprising:

illuminating a patterning array with the radiation beam;

patterning the radiation beam using a patterning array; and

projecting the patterned beam onto a workpiece.