Broad-angle multilayer mirror design

• US 20050213198A1
• Filed: 03/29/2004
• Published: 09/29/2005
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Lee, Sang Hun, Goldstein, Michael
• Granted Patent: US 7,522,335 B2
• Time in Patent Office: Days
• US Class Current: 359/359
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G02B 5/0816 Multilayer mirrors, i.e. having two or more reflecting layers G02B5/0883, G02B5/0891 take precedence
• CPC Class Codes: G02B 5/0891 Ultraviolet [UV] mirrors apparatus for microlithography exposure G03F7/70; X-ray multilayer structures G21K1/06
• CPC Class Codes: G03F 7/70233 Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems
• CPC Class Codes: G03F 7/70316 Details of optical elements, e.g. of Bragg reflectors, extreme ultraviolet [EUV] multilayer or bilayer mirrors or diffractive optical elements
• CPC Class Codes: G03F 7/70958 Optical materials or coatings, e.g. with particular transmittance, reflectance or anti-reflection properties
• CPC Class Codes: G21K 1/062 Devices having a multilayer structure
• CPC Class Codes: G21K 2201/067 Construction details

Abstract

According to one embodiment a broad-angle multilayer (ML) mirror system is disclosed. The ML mirror includes a multiple layer structure configured to provide uniform reflectivity over a wide range of angles with small phase shifts.

Claims

1. A broad-angle multilayer (ML) mirror comprising a multiple layer structure to provide uniform reflectivity over a wide range of angles with small phase shifts.

2. The ML mirror of claim 1 wherein the ML mirror provides an acceptance angle in excess of 20°

without a significant loss of reflectivity.

3. The ML mirror of claim 2 wherein the loss of reflectivity is approximately 17%.

4. The ML mirror of claim 1 wherein the ML mirror increases the relative phase shift.

5. The ML mirror of claim 1 wherein the ML mirror comprises a 13.5 nm central wavelength.

6. The ML mirror of claim 1 wherein the structure comprises:

a substrate layer; and

a plurality of bi-layers to provide a 13.5 nm central wavelength.

7. The ML mirror of claim 6 wherein the plurality of bi-layers have a variable thickness.

8. The ML mirror of claim 6 wherein the plurality of bi-layers include thirty-six bi-layers.

9. The ML mirror of claim 6 wherein the bi-layers are comprised of Mo/Si bi-layers.

10. The ML mirror of claim 6 wherein the bi-layers are comprised of Mo/Be bi-layers.

11. An optical system having an extreme ultra-violet (EUV) radiation source, the system comprising:

a mask;

a wafer; and

a plurality of reflecting surfaces for imaging the mask on the wafer, wherein one or more of the plurality of reflecting surfaces includes a broad-angle multilayer (ML) mirror having a multiple layer structure to provide uniform reflectivity over a wide range of angles with small phase shifts.

12. The system of claim 11 wherein the plurality of reflecting surfaces comprises six mirrors.

13. The system of claim 11 wherein the ML mirror provides an acceptance angle in excess of 20°

without a significant loss of reflectivity.

14. The system of claim 13 wherein the ML mirror has a loss of reflectivity of approximately 17%.

15. The system of claim 11 wherein the ML mirror increases the relative phase shift.

16. The system of claim 11 wherein the ML mirror comprises a 13.5 nm central wavelength.

17. The system of claim 11 wherein the mirror comprises:

a substrate layer; and

a plurality of bi-layers to provide a 13.5 nm central wavelength.

18. The system of claim 17 wherein the plurality of bi-layers have a variable thickness.

19. The system of claim 18 wherein the plurality of bi-layers include thirty-six bi-layers.

20. An optical system having an extreme ultra-violet (EUV) radiation source, the system comprising:

a mask;

a wafer; and

a plurality of reflecting surfaces for imaging the mask on the wafer, including;

a first mirror;

a second mirror,

a third mirror having a multiple layer structure to provide uniform reflectivity over a wide range of angles with small phase shifts;

a fourth mirror;

a fifth mirror; and

a sixth mirror.

21. The system mirror of claim 20 wherein the third mirror provides an acceptance angle in excess of 20°

without a significant loss of reflectivity.

22. The system of claim 21 wherein the third mirror has a loss of reflectivity of approximately 17%.

23. The system mirror of claim 22 wherein the third mirror comprises a 13.5 nm central wavelength.

24. The system of claim 20 wherein the third mirror comprises:

a substrate layer; and

a plurality of bi-layers to provide a 13.5 nm central wavelength.

25. The system of claim 24 wherein the plurality of bi-layers have a variable thickness.

26. The system of claim 24 wherein the plurality of bi-layers include thirty-six bi-layers.