System and method for printing interference patterns having a pitch in a lithography system

• US 20070279642A1
• Filed: 05/31/2006
• Published: 12/06/2007
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Shmarev, Yevgeniy Konstantinovich
• Granted Patent: US 8,934,084 B2
• Time in Patent Office: Days
• US Class Current: 356/521
• CPC Class Codes: G03F 7/70408 Interferometric lithography; Holographic lithography; Self-imaging lithography, e.g. utilizing the Talbot effect

Abstract

An interferometric lithography system produces a pattern having a sharp field edge and minimal optical path length difference. Light passes through a beamsplitter into an input prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the input prism toward a substrate prism. The substrate prism is symmetric to the input prism such that the incidence angle at an image plane is approximately equal to the beamsplitter diffraction angle. Alternatively, light passes through a beamsplitter into a prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the prism toward an output surface of the prism, such that the incidence angle at the output surface is approximately equal to the beamsplitter diffraction angle. A plurality of these interferometers can be stacked, each being optimized for a given pitch, such that the stack provides a variable pitch interferometry system.

Claims

1. An interferometric lithography apparatus, comprising along an optical path:

a beam splitter to create at least two spatially coherent radiation beams; and

;

a beam combiner adapted to redirect and combine the two spatially coherent radiation beams onto a surface of a substrate to form an interference pattern;

wherein the interferometric lithography apparatus is provided with a field blade and a lens for imaging a border of the field blade onto the surface of the substrate so as to create the border of the interference pattern.

2. The interferometric lithography apparatus of claim 1, wherein the beam splitter is provided with a grating and the apparatus further comprises:

a zero diffraction order light blocker between the beam splitter and the beam combiner for blocking the zero order diffracted light of the grating.

3. The interferometric lithography apparatus of claim 2, wherein apparatus comprises:

a first and second afocal imaging branch provided with the lens, and located on two opposite sides of the light blocker between the beam splitter and the beam combiner.

4. The interferometric lithography apparatus of claim 3, wherein the first and second afocal imaging branch to reduce shear in light passing through the and second afocal imaging branch.

5. The interferometric lithography apparatus of claim 3, further comprising:

lenses placed symmetrically around a convergence point in the first and second afocal imaging branch to reduce shear in light passing through the first and second afocal imaging branch.

6. The interferometric lithography apparatus of claim 1, wherein the beam combiner comprises a reflecting surface.

7. The interferometric lithography apparatus of claim 1, wherein the beam splitter is provided with the field blade.

8. The interferometric lithography apparatus of claim 1, wherein the field blade defines a rectangular border onto the surface of the substrate.

9. The interferometric lithography apparatus of claim 1, wherein an immersion liquid fills a gap between the beam combiner and the surface of the substrate.

10. The interferometric lithography apparatus of claim 6, wherein a pitch of the diffraction grating is approximately equal to twice a pitch of a pattern to be patterned onto the surface of the substrate.

11. An interferometric lithography apparatus, comprising:

a beam splitter to create at least two spatially coherent radiation beams;

a beam combiner adapted to redirect and combine the two spatially coherent radiation beams onto a surface of a substrate to form an interference pattern; and

four reflecting surfaces between the beam splitter and an output surface of the beam combiner which faces the surface of the substrate.

12. An interferometric lithography apparatus of claim 11, wherein the beam splitter comprises a grating and a blocking aperture for blocking zero diffraction order light of the grating.

13. The interferometric lithography apparatus of claim 12, wherein a pitch of the grating is approximately equal to twice a pitch of an interference pattern to be patterned at the surface of the substrate.

14. The interferometric lithography apparatus of claim 13, wherein light passing through the beam combiner and the surface of the substrate.

15. The interferometric lithography apparatus of claim 11, further comprising field blades, wherein the apparatus comprises lenses to image a border of the field blades onto the surface of the substrate to create a border for the interference pattern to be patterned.

16. An interferometric lithography apparatus having variable pitch, comprising:

an illumination system;

a first interferometer to form an interference pattern having a first pitch; and

a second interferometer to form an interference pattern having a second pitch,

wherein the first and second interferometers are movable with respect to the illumination system such that light from the illumination system is incident on one of the first and second interferometers.

17. The interferometric lithography apparatus of claim 16, wherein the first interferometer comprises:

a beam splitter to create at least two spatially coherent radiation beams; and

a beam combiner adapted to redirect and combine the two spatially coherent radiation beams onto a surface of a substrate to form an interference pattern having the first pitch.

18. The interferometric lithography apparatus of claim 17, wherein the beam splitter comprises a grating to create the at least two spatially coherent radiation beams.

19. The interferometric lithography apparatus of claim 16, wherein the first and second interferometers are arranged in a stack formation.

20. The interferometric lithography apparatus of claim 17, wherein the beam combiner comprises a reflecting surface.