Lithographic projection apparatus, reflector assembly for use therein, and device manufacturing method

• US 20060250599A1
• Filed: 07/07/2006
• Published: 11/09/2006
• Est. Priority Date: 08/15/2002
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Bakker, Levinus Pieter, Visser, Hugo Matthieu, Jonkers, Jeroen, Schuurmans, Frank Jeroen Pieter
• Granted Patent: US 7,852,460 B2
• Time in Patent Office: Days
• US Class Current: 355/67
• 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 17/004 Systems comprising a plurality of reflections between two or more surfaces, e.g. cells, resonators multipass arrangements for optical cuvettes G01N21/031; laser resonators H01S3/05
• CPC Class Codes: G02B 17/006 Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses Fresnel mirrors G02B5/09, Fresnel lenses G02B3/08
• CPC Class Codes: G02B 27/0043 in projection exposure systems, e.g. microlithographic systems
• CPC Class Codes: G03F 7/70166 Capillary or channel elements, e.g. nested extreme ultraviolet [EUV] mirrors or shells, optical fibers or light guides
• CPC Class Codes: G03F 7/70175 Lamphouse reflector arrangements or collector mirrors, i.e. collecting light from solid angle upstream of the light source
• CPC Class Codes: G03F 7/70891 Temperature
• CPC Class Codes: G03F 7/70916 Pollution mitigation, i.e. mitigating effect of contamination or debris, e.g. foil traps

Abstract

A lithographic projection apparatus includes a reflector assembly, the reflector assembly includes a first and a second reflector extending in a direction of an optical axis, the first and second reflector each having a reflective surface, a backing surface and an entry section at respectively a first and a second distance from the optical axis, the first distance being larger than the second distance, rays deriving from a point on the optical axis being cut off by the entry sections of the first and second reflectors and being reflected on the reflective surface of the first reflector and defining a high radiation intensity zone and a low radiation intensity zone between the reflectors; a radial support member configured to support the reflectors extending in the low radiation intensity zone, wherein the radial support member creates a shade in a downstream direction of the optical axis and a virtual shade in an upstream direction of the optical axis; and a structure placed in the virtual shade.

Claims

1. A reflector assembly for use in a lithographic projection apparatus, the reflector assembly comprising:

a first and a second reflector extending in a direction of an optical axis, the first and second reflector each having a reflective surface, a backing surface and an entry section at respectively a first and a second distance from the optical axis, the first distance being larger than the second distance, rays deriving from a point on the optical axis being cut off by the entry sections of the first and second reflectors and being reflected on the reflective surface of the first reflector and defining a high radiation intensity zone and a low radiation intensity zone between the reflectors;

a radial support member configured to support the reflectors extending in the low radiation intensity zone, wherein the radial support member creates a shade in a downstream direction of the optical axis and a virtual shade in an upstream direction of the optical axis; and

a structure placed in the virtual shade.

2. A reflector assembly according to claim 1, wherein the structure in the virtual shade comprises a nozzle for directing a fluid in the direction of the input sections of the reflectors.

3. A reflector assembly according to claim 2, wherein the fluid is substantially transparent to EUV radiation with a wavelength between 5-20 nm.

4. A reflector assembly according to claim 2, further comprising a fluid removal unit located near the entry sections of the reflectors.

5. A reflector assembly according to claim 1, wherein the structure in the virtual shade comprises a heat transfer device.

6. A reflector assembly according to claim 5, wherein the heat transfer device comprises fluid ducts extending in the virtual shade.

7. A reflector assembly according to claim 1, wherein the structure in the virtual shade comprises a transducer configured to form a signal and connected to a signal lead configured to supply the signal to a processing member located at a distance from the reflectors.

8. A reflector assembly according to claim 1, wherein the structure in the virtual shade comprises an actuator configured to adjust a position of the first reflector and/or the second reflector.

9. A lithographic projection apparatus, comprising:

a radiation system configured to form a projection beam of radiation from radiation emitted by a radiation source;

a support configured to hold a patterning device which is to be irradiated by the projection beam, the patterning device configured to pattern the projection beam,

a substrate table configured to hold a substrate; and

a projection system configured to image an irradiated portion of the patterning device onto a target portion of the substrate, the radiation system comprising a reflector assembly comprising

a first and a second reflector extending in a direction of an optical axis, the first and second reflector each having a reflective surface, a backing surface and an entry section at respectively a first and a second distance from the optical axis, the first distance being larger than the second distance, rays deriving from a point on the optical axis being cut off by the entry sections of the first and second reflectors and being reflected on the reflective surface of the first reflector and defining a high radiation intensity zone and a low radiation intensity zone between the reflectors;

a radial support member configured to support the reflectors extending in the low radiation intensity zone, wherein the radial support member creates a shade in a downstream direction of the optical axis and a virtual shade in an upstream direction of the optical axis; and

a structure placed in the virtual shade.

10. A lithographic apparatus according to claim 9, wherein the structure in the virtual shade comprises a nozzle for directing a fluid in the direction of the input sections of the reflectors.

11. A lithographic apparatus according to claim 10, wherein the fluid is substantially transparent to EUV radiation with a wavelength between 5-20 nm.

12. A lithographic apparatus according to claim 10, further comprising a fluid removal unit located near the entry sections of the reflectors.

13. A lithographic apparatus according to claim 9, wherein the structure in the virtual shade comprises a heat transfer device.

14. A lithographic apparatus according to claim 13, wherein the heat transfer device comprises fluid ducts extending in the virtual shade.

15. A lithographic apparatus according to claim 9, wherein the structure in the virtual shade comprises a transducer configured to form a signal and connected to a signal lead configured to supply the signal to a processing member located at a distance from the reflectors.

16. A lithographic apparatus according to claim 9, wherein the structure in the virtual shade comprises an actuator configured to adjust a position of the first reflector and/or the second reflector.

17. A lithographic apparatus according to claim 12, wherein the reflectors are placed in a chamber having an opening comprising a pressure reduction member, the radiation source is placed in an adjacent source housing and emits radiation through the pressure reduction member, the fluid removal unit is associated with the chamber for removing fluid near the pressure reduction member, and a second fluid removal unit is associated with the source housing.