Method of determining optical properties and projection exposure system comprising a wavefront detection system

• US 20060231731A1
• Filed: 03/24/2006
• Published: 10/19/2006
• Est. Priority Date: 09/26/2003
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Inventors: Wegmann, Ulrich, Lauer, Steffen, Sakowski, Harald, Emer, Wolfgang, Schriever, Martin
• Granted Patent: US 7,230,220 B2
• Time in Patent Office: Days
• US Class Current: 250/201.900
• CPC Class Codes: G03F 7/70258 Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system
• CPC Class Codes: G03F 7/706 Aberration measurement

Abstract

A method of determining at least one optical property of a projection exposure system is described, wherein the exposure system includes a beam delivery system having a light source for generating an exposure optical beam having light of a first wavelength (λ₁) and a second wavelength (λ₂), wherein a first ratio is defined as an intensity of light λ₂ to an intensity of light λ₁ in the exposure optical beam. The method includes supplying at least one measuring optical beam including light of at least λ₁ to the projection optical system, detecting wavefronts having traversed the projection optical system, and determining an optical property in dependence of the detected wavefronts, wherein a second ratio of an intensity of light of λ₂ to an intensity of light of λ₁ in the measuring optical beam being incident on the detector of the wavefront detection system is less than the first ratio.

Claims

1. A method of determining optical properties of a projection exposure system, the projection exposure system comprising a beam delivery system for supplying an exposure optical beam for illuminating a patterning structure and comprising a projection optical system for imaging the patterning structure onto a photosensitive substrate, wherein the beam delivery system comprises a light source generating the exposure optical beam having light of a first wavelength and of at least a second wavelength different from the first wavelength, wherein a first ratio is defined as an intensity of light of the second wavelength in the exposure optical beam to an intensity of light of the first wavelength in the exposure optical beam, wherein the method comprises:

supplying at least one measuring optical beam to the projection optical system, the at least one measuring optical beam comprising light of the first wavelength and having wavefronts; and

detecting wavefronts of the at least one measuring optical beam having traversed the projection optical system and determining the optical properties in dependence of the detected wavefronts,

wherein a second ratio of an intensity of light of the second wavelength in the at least one measuring optical beam having traversed the projection optical system and being incident on a detector of a wavefront detection system to an intensity of light of the first wavelength in the at least one measuring optical beam having traversed the projection optical system and being incident on the detector of the wavefront detection system is less than the first ratio.

an exposure optical beam for illuminating a patterning structure and comprising a projection optical system for imaging the patterning structure onto a photosensitive substrate, wherein the beam delivery system comprises a light source generating light of a first wavelength and of at least a second wavelength different from the first wavelength, wherein a first ratio is defined as an intensity of light of the second wavelength in the exposure optical beam to an intensity of light of the first wavelength in the exposure optical beam, wherein the method comprises;

supplying at least one measuring optical beam to the projection optical system, the at least one measuring optical beam comprising light of the first wavelength and at least the second wavelength and having wavefronts;

detecting wavefronts of the at least one measuring optical beam having traversed the projection optical system and determining an optical property in dependence of the detected wavefronts; and

wherein the detecting and determining includes correcting for contributions of the light of the second wavelength.

10. The method of claim 9, wherein the detecting wavefronts comprises detecting of a first light pattern generated from the at least one measuring optical beam having traversed the projection optical system, and wherein the correcting includes determining a second light pattern generated by light of the second wavelength.

11. The method of claim 9, wherein the detecting wavefronts comprises detecting a first light pattern generated from the at least one measuring optical beam having traversed delivery system comprises a light source generating light of a first wavelength and of at least a second wavelength different from the first wavelength, wherein a first ratio is defined as an intensity of light of the second wavelength in the exposure optical beam to an intensity of light of the first wavelength in the exposure optical beam;

a projection optical system for imaging the reticle onto a photosensitive substrate; and

a wavefront detection system having a detector for detecting light from the light source having traversed the projection optical system and a filter for reducing the first ratio, wherein the filter is positioned or positionable in a beam path between the light source and the detector.

17. The projection exposure system of claim 16, wherein the filter is positioned or positionable in one of:

a space between the light source and the projection optical system and a space between the projection optical system and the detector.

18. The projection exposure system of claim 17, wherein the wavefront detection system comprises a Hartmann-Shack sensor system.

19. The projection exposure system of claim 17, wherein the wavefront detection system comprises a Hartmann-type sensor system.

20. The projection exposure system of claim 17, wherein the wavefront detection system comprises an interferometer system.

21. The projection exposure system of claim 20, wherein the interferometer system comprises a shearing interferometer.

22. The projection exposure system of claim 20, wherein the interferometer system comprises a point diffraction interferometer.

23. The projection exposure system of claim 17, further comprising a system for positioning the filter in the beam path and removing the filter from the beam path.

24. The projection exposure system of claim 17, wherein the system is configured for the filter to be positioned in the beam path in a measuring mode and for the filter to be removed from the beam path in an exposure mode.

25. A method of manufacturing a miniaturised device comprising:

aligning a projection exposure system according to the method of claim 14;

imaging a patterning structure onto the photosensitive substrate using the projection exposure system; and

processing the photosensitive substrate to fabricate the miniaturised device.

26. A miniaturised device manufactured according to the method of claim 25.