EUV exposure apparatus with reflective elements having reduced influence of temperature variation

• US 10,684,551 B2
• Filed: 04/23/2019
• Issued: 06/16/2020
• Est. Priority Date: 07/30/2010
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Inventors: Baer, Norman, Loering, Ulrich, Natt, Oliver, Wittich, Gero, Laufer, Timo, Kuerz, Peter, Limbach, Guido, Hembacher, Stefan, Walter, Holger, Kwan, Yim-Bun-Patrick, Hauf, Markus, Stickel, Franz-Josef, Van Schoot, Jan
• Primary Examiner(s): Iacoletti, Michelle M
• Application Number:
  US16/392,220
• Publication Number:
  US 20190310555A1
• Time in Patent Office: 420 Days
• Field of Search: None
• 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 17/0647 using more than three curved mirrors G02B17/0668, G02B17/0694 take precedence
• CPC Class Codes: G02B 27/0043 in projection exposure systems, e.g. microlithographic systems
• CPC Class Codes: G02B 3/00 Simple or compound lenses
• CPC Class Codes: G02B 5/00 Optical elements other than lenses light guides G02B6/00; optical logic elements G02F3/00
• CPC Class Codes: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08
• 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: G02B 7/1815 with cooling or heating systems cooling arrangements for laser mirrors H01S3/0401
• CPC Class Codes: G03B 27/542 for copying cameras, reflex exposure lighting
• CPC Class Codes: G03F 7/7015 Details of optical elements
• CPC Class Codes: G03F 7/702 Reflective illumination, i.e. reflective optical elements other than folding mirrors, e.g. extreme ultraviolet [EUV] illumination systems
• 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 7/70825 Mounting of individual elements, e.g. mounts, holders or supports workpiece or mask holders G03F7/707
• CPC Class Codes: G03F 7/70891 Temperature
• 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 2201/061 characterised by a multilayer structure
• CPC Class Codes: G21K 2201/064 having a curved surface

Abstract

A projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.

Claims

1. A projection lens of an EUV-lithographic projection exposure system, comprising:

a plurality of reflective optical elements M_i, each comprising

a body MB_i and a reflective surface MS_i for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light with a wavelength in a wavelength range of less than 50 nm being reflected from the reticle while illuminated by an illumination system of the EUV-lithographic projection exposure system, wherein the lens comprises

support means for passively or actively supporting at least one optical element M_k,

a pressure control system for the control of the pressure Δ

p within a surrounding of the at least one reflective optical element M_k,

wherein the control is based on a parameter selected from a group consisting of the temperature of the optical element M_k, the time, a parameter which directly or indirectly influences the temperature of the optical element M_k, an illumination setting, a change of the reticle, thermally or mechanically induced optical aberration data of the optical element M_k or the projection lens and an output parameter from a model,

the model input comprising data selected from the group consisting of the temperature of the reflective optical element M_k, the time, a parameter which directly or indirectly influences the temperature of the optical element M_k, an illumination setting, thermally or mechanically induced optical aberration data of the optical element M_k or the projection lens and a change of the reticle,

the support means comprising a temperature sensitive element selected from a group consisting of linking points, bipod structures, linking elements, support element and housing structure, for passively or actively supporting the at least one optical element M_k, wherein the temperature sensitive element is controlled to a predefined temperature by a cooler, and,

the cooler being spatially arranged between the temperature sensitive element and the at least one optical element Mk.

2. The projection lens according to claim 1, wherein the pressure Δ

p within the surrounding of the at least one optical element M_k is in a range of 0.1 Pa to 10 Pa.

3. The projection lens according to claim 1, wherein the distance between the at least one optical element M_k and the cooler is in a range of 1 mm to 10 mm.

4. The projection lens according to claim 1, wherein the pressure control system comprises at least one of a gas inlet and a gas outlet nearby the at least one reflective optical element M_k.

5. The projection lens according to claim 1, wherein the distance of the cooler to the at least one reflective optical element M_k is adjustable to control a heat transfer between these elements.

6. The projection lens according to claim 1, wherein the at least one reflective optical element M_k comprises a material with a temperature dependent coefficient of thermal expansion which is zero at a zero cross temperature T_0k.

7. The project lens according to claim 6, wherein the zero cross temperature is different from the predefined temperature of the temperature sensitive element.

8. The projection lens according to claim 6, wherein the pressure Δ

p, controlled by the control system, is such that the temperature of the at least one optical element M_k is at the zero cross temperature.

9. A projection lens of an EUV-lithographic projection exposure system, comprising

a plurality of reflective optical elements M_i, each comprising

a body MB_i and a reflective surface MS_i for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light with a wavelength in a wavelength range of less than 50 nm being reflected from the reticle while illuminated by an illumination system of the EUV-lithographic projection exposure system, wherein the lens comprises

support means for passively or actively supporting at least one optical element M_k, and,

a pressure control system for the control of the pressure Δ

p within a surrounding of the at least one reflective optical element M_k,

wherein the control is based on a parameter selected from a group including the temperature of the optical element M_k, the time, a parameter which directly or indirectly influences the temperature of the optical element M_k, an illumination setting, a change of the reticle, thermally or mechanically induced optical aberration data of the optical element M_k or the projection lens and an output parameter from a model,

the model input comprising data selected from the group including the temperature of the reflective optical element M_k, the time, a parameter which directly or indirectly influences the temperature of the optical element M_k, an illumination setting, thermally or mechanically induced optical aberration data of the optical element M_k or the projection lens and a change of the reticle,

wherein the support means includes a temperature sensitive element selected from a group including linking points, bipod structures, linking elements, support element and housing structure, for passively or actively supporting the at least one optical element M_k, wherein the temperature sensitive element is controlled to a predefined temperature by a cooler, and,

wherein the cooler is spatially arranged between the temperature sensitive element and the at least one optical element M_k.