Optical element with a self-assembled monolayer, lithographic projection apparatus including such an optical element, and device manufacturing method

• US 20050157283A1
• Filed: 02/08/2005
• Published: 07/21/2005
• Est. Priority Date: 06/14/2002
• Status: Abandoned Application

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Kurt, Ralph, Wijdenes, Jacob
• Application Number:
  US11/052,115
• Publication Number:
  US 20050157283A1
• Time in Patent Office: Days
• US Class Current: 355/67
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G03F 1/24 Reflection masks; Preparation thereof
• CPC Class Codes: G03F 1/48 Protective coatings
• CPC Class Codes: G03F 7/70958 Optical materials or coatings, e.g. with particular transmittance, reflectance or anti-reflection properties

Abstract

A lithographic apparatus contains an optical element, the surface of the optical element being modified to reduce the effects of reflectivity reduction by molecular contamination. The surface includes a self assembled monolayer.

Claims

1. A lithographic projection apparatus, comprising:

a radiation system configured to provide a beam of EUV radiation;

a support configured to support a patterning device, the patterning device configured to pattern the beam of radiation according to a desired pattern;

a substrate table configured to hold a substrate; and

a projection system configured to project the patterned beam onto a target portion of the substrate, wherein the radiation system and/or the projection system contains an optical element comprising

a substrate;

a Mo/Si multilayer stack on the substrate; and

a hydrophobic self-assembled monolayer on the multilayer stack.

2. An apparatus according to claim 1, wherein the optical element has a peak reflectivity for radiation having a wavelength of about 5 nm to about 50 nm.

3. An apparatus according to claim 2, wherein the reflectivity of the optical element is greater than about 40%.

4. An apparatus according to claim 1, wherein the optical element is a near-normal incidence mirror, a grazing incidence mirror, an integrator, or a sensor.

5. An apparatus according to claim 4, wherein the near-normal incidence mirror is a Mo/Si multilayer mirror.

6. An apparatus according to claim 4, wherein the integrator is a scattering plate.

7. An apparatus according to claim 4, wherein the sensor is an image sensor or a spot sensor.

8. An apparatus according to claim 1, wherein the self-assembled monolayer covers about 70% of a the multilayer stack.

9. An optical element, comprising:

a substrate;

a Mo/Si multilayer stack on the substrate; and

a hydrophobic self-assembled monolayer on the multilayer stack.

10. An optical element according to claim 9, wherein the optical element has a peak reflectivity for radiation with a wavelength of about 5 nm to about 50 nm.

11. An optical element according to claim 9, wherein the reflectivity of the optical element is greater than about 40%.

12. An optical element according to claim 9, wherein the optical element is a near-normal incidence mirror, a grazing incidence mirror, an integrator, or a sensor.

13. An optical element according to claim 12, wherein the near-normal incidence mirror is a Mo/Si multilayer mirror.

14. An optical element according to claim 12, wherein the integrator is a scattering plate.

15. An optical element according to claim 12, wherein the sensor is an image sensor or a spot sensor.

16. An optical element according to claim 9, wherein the self-assembled monolayer covers about 70% of the multilayer stack.

17. A device manufacturing method, comprising:

providing a beam of radiation;

patterning the beam of radiation; and

projecting the patterned beam of radiation onto a target portion of a substrate, wherein at least one optical element on which the beam of radiation is incident has, on its surface, a hydrophobic self-assembled monolayer.

18. A method according to claim 17, wherein the optical element has a peak reflectivity for radiation having a wavelength of about 5 nm to about 50 mm.

19. A method according to claim 17, wherein the reflectivity of the optical element is greater than about 40%.

20. A method according to claim 17, wherein the self-assembled monolayer covers about 70% of a surface of the optical element.