Microlithography projection objective with crystal lens

• US 7,755,839 B2
• Filed: 12/15/2004
• Issued: 07/13/2010
• Est. Priority Date: 12/19/2003
• Status: Expired due to Fees

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Inventors: Schuster, Karl-Heinz, Clauss, Wilfried
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US10/596,626
• Publication Number:
  US 20070091451A1
• Time in Patent Office: 2,036 Days
• Field of Search: 359649-651, 359355-357, 355/53, 355/55, 355 67- 71, 355/77, 430/321
• US Class Current: 359/649
• CPC Class Codes: G02B 1/02 made of crystals, e.g. rock-salt, semi-conductors G02B1/08 takes precedence
• CPC Class Codes: G02B 13/143 for use with ultraviolet radiation
• CPC Class Codes: G03F 7/70241 Optical aspects of refractive lens systems, i.e. comprising only refractive elements
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/7035 Proximity or contact printers
• CPC Class Codes: G03F 7/70958 Optical materials or coatings, e.g. with particular transmittance, reflectance or anti-reflection properties

Abstract

Very high aperture microlithography projection objectives operating at the wavelengths of 248 nm, 193 nm and also 157 nm, suitable for optical immersion or near-field operation with aperture values that can exceed 1.4 are made feasible with crystalline lenses and crystalline end plates P of NaCl, KCl, KI, RbI, CsI, and MgO, YAG with refractive indices up to and above 2.0. These crystalline lenses and end plates are placed between the system aperture stop AS and the wafer W, preferably as the last lenses on the image side of the objective.

Claims

1. Microlithography projection objective comprising a numerical aperture on the image side equal to or larger than 1.0, containing at least one lens of a crystal material from the group that consisting of NaCl, KCl, KI, NaI, RbI, CsI, MgO, MgAl₂O₄ and Y₃Al₅O₁₂.

2. Microlithography projection objective according to claim 1, characterized in that the last curved lens on the image side comprises one of the crystal materials named.

3. Microlithography projection objective according to claim 1 or claim 2, wherein the numerical aperture on the image side is more than 1.40.

4. Microlithography projection objective according to claim 1 or claim 2, wherein at least one lens of one of the named crystal materials has a moisture protection coating.

5. Microlithography projection objective according to claim 1 or claim 2, wherein a plurality of lenses comprise one of the crystal materials, and that the index of refraction at an operating wavelength is highest for the lens that is arranged nearest to an image plane of the projection objective.

6. Microlithography projection objective according to claim 1 or claim 2, wherein the objective is configured as an immersion objective.

7. Microlithography projection objective according to claim 1 or claim 2, wherein the objective is configured as an optical-near-field objective.

8. Microlithography projection objective according to claim 1 or claim 2, wherein the objective has an operating wavelength from the group consisting of 248 nm, 193 nm and 157 nm.

9. Microlithography projection objective according to claim 1 or claim 2, wherein at least one of the lenses of one of the crystal materials named is composed of at least two lens components that are oriented with different crystallographic orientations.

10. Microlithography projection objective according to claim 1 or claim 2, wherein at least one lens is composed of a plurality of components and that at least one of said components consists of a crystal material.

11. Microlithography projection objective according to claim 1 or claim 2, wherein the numerical aperture on the image side is more than 1.65.

12. Microlithography projection objective according to claim 1 or claim 2, wherein the numerical aperture on the image side is more than 2.0.

13. Microlithography projection objective according to claim 1 or claim 2, wherein said plurality of lenses comprise different ones of the crystal materials named.

14. Microlithography projection objective having a plurality of lenses comprising one of the crystal material from the group that consisting of NaCl, KCl, KI, NaI, RbI, CsI, MgO, MgAl₂O₄ and Y₃Al₅O₁₂, wherein the index of refraction at an operating wavelength is highest for the lens that is arranged nearest to an image plane of the projection objective.