Method of optimizing imaging performance

• US 20050237506A1
• Filed: 04/11/2005
• Published: 10/27/2005
• Est. Priority Date: 04/09/2004
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Inventors: Maul, Manfred, Wegmann, Ulrich, Reisinger, Gerd, Graeupner, Paul, Schriever, Martin
• Granted Patent: US 7,233,386 B2
• Time in Patent Office: Days
• US Class Current: 355/55
• CPC Class Codes: G03B 27/52 Details
• CPC Class Codes: G03F 7/70191 Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like
• CPC Class Codes: G03F 7/70216 Mask projection systems

Abstract

A method of optimizing an imaging performance of a projection exposure system is provided, wherein the projection exposure system comprises an illumination optical system for illuminating a patterning structure and a projection optical system for imaging a region of the illuminated patterning structure onto a corresponding field. The method comprises setting the field to a first exposure field, setting optical parameters of the projection exposure system to a first setting such that the imaging performance within the first exposure field is a first optimum performance, changing the field to a second exposure field, and changing the optical parameters to a second setting such that the imaging performance within the second exposure field is a second optimum performance.

Claims

1. A method of optimizing an imaging performance of a projection exposure system,

the projection exposure system comprising an illumination optical system including a light source for illuminating a patterning structure and a projection optical system for imaging a region of the illuminated patterning structure onto a corresponding field in a substrate-plane,

the method comprising:

setting the field to a first exposure field, the first exposure field having first field dimensions and a first position within a maximum field exposable by the projection exposure system;

setting optical parameters of the projection exposure system to a first setting such that an imaging performance quantity within the first exposure field at the first setting satisfies a first performance condition;

changing the field to a second exposure field, the second exposure field having at least one of second field dimensions different from the first field dimensions and a second position within the maximum field exposable by the projection exposure system, which second position is different from the first position; and

changing the optical parameters of the projection exposure system to a second setting such that an imaging performance quantity within the second exposure field at the second setting satisfies a second performance condition,

wherein the imaging performance quantity associated with the second exposure field at the second setting is better than an imaging performance quantity associated with the second exposure field at the first setting.

2. The method of claim 1, wherein the imaging performance quantities within the first and second exposure fields are determined in dependence of at least one imaging characteristic at a plurality of positions within the respective field.

3. The method of claim 2 wherein the at least one imaging characteristic is selected from the group comprising aberration, uniformity, telecentricity, transmission, illumination efficiency and polarization.

4. The method of claim 2, further comprising measuring the at least one imaging characteristic and determining the optical parameters in dependence of the at least one measured imaging characteristic.

5. The method of claim 1, further comprising determining optical parameters for a plurality of second settings for a plurality of at least one of second field dimensions and second positions and storing the optical parameters of the plurality of second settings associated with the at least one of second field dimensions and positions.

6. The method of claim 5, further comprising determining the optical parameters of the second setting in dependence of a plurality of stored optical parameters in dependence of the at least one of second field dimensions and positions.

7. The method of claim 6, wherein the stored optical parameters are the stored optical parameters determined in dependence of the at least one measured imaging characteristic.

8. The method of claim 1, wherein changing of the optical parameters includes at least one of changing a position of the patterning structure, changing a position of the substrate, changing a gas pressure in a volume between adjacent optical elements of the projection exposure system, changing a refractive index in a volume between adjacent optical elements of the projection exposure system, changing a wavelength of light illuminating the patterning structure, displacing an optical element of the projection exposure system with respect to other optical elements thereof, deforming an optical element of the projection exposure system, changing a transmission characteristic of an optical element of the projection exposure system, replacing an optical element of the projection exposure system with another optical element, and changing an aperture of a diaphragm provided in the projection exposure system.

9. The method of claim 1, wherein the first and second exposure fields are used for exposing substrates in a manufacturing process of miniaturized articles formed from the exposed substrates.

10. The method of claim 1, wherein an optical axis of the projection exposure system intersects the substrate-plane outside of at least one of the first and second exposure fields.

26. The method of claim 1, wherein the projection exposure system is a scanning type exposure system.

28. A projection exposure system comprising an illumination optical system including a light source for illuminating a patterning structure and a projection optical system for imaging a region of the illuminated patterning structure into a corresponding field in a substrate-plane, which is adapted to carry out the method according to claim 1.

33. A projection exposure system adapted to carry out the method according to claim 1, wherein the projection exposure system comprises an illumination optical system having a pupil plane and including a light source for illuminating a patterning structure and a projection optical system for imaging a region of the illuminated patterning structure into a corresponding field in a substrate-plane for exposing substrates with images of the patterning structure in a manufacturing process of miniaturized articles formed from the exposed substrates,

wherein the illumination optical system comprises

a first optical integrator system for illuminating a first region of a first size of the patterning structure, and

at least a second optical integrator system for illuminating a second region of the patterning structure which has a second size which is different from the first size wherein the first and at least second optical integrator are arranged such that the first optical integrator can be exchanged for the at least second optical integrator system, and

wherein a distribution of illumination intensity in a pupil plane of the illumination optical system in terms of shape and size is substantially the same for the first and at least second optical integrator system.

11. A method of optimizing an imaging performance of a projection exposure system,

the projection exposure system comprising an illumination optical system including a light source for illuminating a patterning structure and a projection optical system for imaging a region of the illuminated patterning structure onto a corresponding field in a substrate-plane,

the method comprising:

setting the field to a first exposure field, the first exposure field having first field dimensions and a first position within a maximum field exposable by the projection exposure system;

setting optical parameters of the projection exposure system to a first setting such that the imaging performance within the first exposure field is a first substantially optimum performance;

changing the field to a second exposure field, the second exposure field having at least one of second field dimensions different from the first field dimensions and a second position within the maximum field exposable by the projection exposure system, which second position is different from the first position; and

changing the optical parameters of the projection exposure system to a second setting such that the imaging performance within the second exposure field is a second substantially optimum performance,

wherein the imaging performance within the second exposure field in the second setting is better than an imaging performance within the second exposure field in the first setting.

22. The method of claim 11, wherein setting the optical parameters includes at least one of setting a position of the patterning structure, setting a position of the substrate, changing a gas pressure in a volume between adjacent optical elements of the projection exposure system, setting a refractive index in a volume between adjacent optical elements of the projection exposure system, setting a wavelength of light illuminating the patterning structure, displacing an optical element of the projection exposure system with respect to other optical elements thereof, deforming an optical element of the projection exposure system, setting a transmission characteristic of an optical element of the projection exposure system, replacing an optical element of the projection exposure system with another optical element, and setting an aperture of a diaphragm provided in the projection exposure system.

12. A method of optimizing an imaging performance of a projection exposure system, the projection exposure system comprising

an illumination optical system including a light source for illuminating a patterning structure, and

a projection optical system for imaging a region of the illuminated patterning structure onto a corresponding field in a substrate-plane, which region comprises a first sub-region,

wherein the first sub-region of the patterning structure is imaged onto a corresponding first sub-field within the corresponding field in the substrate-plane,

the method comprising:

setting the field to an exposure field, the exposure field having field dimensions and the first sub-field having first sub-field dimensions and a first sub-field position within the exposure field, wherein the first sub-field dimensions are different from the field dimensions; and

setting optical parameters of the projection exposure system to a setting wherein

an imaging performance quantity within the first sub-field satisfies a first performance condition with regard to a first imaging characteristic, and

the imaging performance quantity with regard to the first imaging characteristic is better within the first sub-field than an imaging performance quantity within an area within the exposure field which is situated outside the first sub-field.

13. The method of claim 12,

wherein the first sub-region of the patterning structure comprises features of a first type, wherein satisfying the first performance condition with regard to the first imaging characteristic within the first sub-field permits imaging the features of the first type at a predetermined quality level for a subsequent production process.

14. The method of claim 12,

wherein the patterning structure further comprises a second sub-region,

wherein the second sub-region is imaged onto a corresponding second sub-field within the corresponding field in the substrate-plane,

the second sub-field having second sub-field dimensions and a second sub-field position which is different from the first sub-field position within the exposure field,

wherein the setting is also such that

an imaging performance quantity within the second sub-field satisfies a second performance condition with regard to a second imaging characteristic different from the first imaging characteristic and such that

the imaging performance quantity with regard to the second imaging characteristic is better within the second sub-field than an imaging performance quantity within an area within the exposure field which is situated outside the second sub-field.

15. The method of claim 14, wherein the second sub-region of the patterning structure comprises features of a second type, wherein satisfying the second performance condition with regard to the second imaging characteristic within the second sub-field permits imaging the features of the second type at a predetermined quality level for a subsequent production process.

16. The method of claim 12, wherein each imaging performance quantity within a respective sub-field is determined based on the respective imaging characteristic at a plurality of positions within the respective sub-field.

17. The method of claim 12, wherein each imaging characteristic is selected from the group comprising aberration, uniformity, telecentricity, transmission, illumination efficiency and polarization.

18. The method of claim 12, further comprising measuring the respective imaging characteristic and determining the optical parameters in dependence of the measured imaging characteristic.

19. The method of claim 12, further comprising determining optical parameters for a plurality of settings for a plurality of at least one of sub-field dimensions and positions and storing the optical parameters of the plurality of settings associated with the at least one of sub-field dimensions and positions.

20. The method of claim 19, further comprising determining the optical parameters of the setting in dependence of a plurality of stored optical parameters in dependence of the at least one of sub-field dimensions and positions.

21. The method of claim 20, wherein the stored optical parameters are the stored optical parameters determined in dependence of the measured imaging characteristic.

23. The method of claim 12, wherein setting the optical parameters includes at least one of setting a position of the patterning structure, setting a position of the substrate, changing a gas pressure in a volume between adjacent optical elements of the projection optical system, setting a refractive index in a volume between adjacent optical elements of the projection optical system, setting a wavelength of light illuminating the patterning structure, displacing an optical element of the projection optical system with respect to other optical elements thereof, deforming an optical element of the projection optical system, setting a transmission characteristic of an optical element of the projection optical system, replacing an optical element of the projection optical system with another optical element, setting an aperture of a diaphragm provided in the projection optical system.

24. The method of claim 12, wherein an optical axis of the projection exposure system intersects the substrate-plane outside of the exposure field.

25. The method of claim 12, wherein the exposure field is used for exposing substrates with images of the patterning structure in a manufacturing process of miniaturized articles formed from the exposed substrates.

27. A method of optimizing an imaging performance of a projection exposure system,

the projection exposure system comprising

an illumination optical system including a light source for illuminating a patterning structure, and

a projection optical system for imaging a region of the illuminated patterning structure onto a corresponding field in a substrate-plane, which region comprises a first sub-region,

wherein the first sub-region of the patterning structure is imaged onto a corresponding first sub-field within the corresponding field in the substrate-plane,

the method comprising:

setting the field to an exposure field, the exposure field having field dimensions and the first sub-field having first sub-field dimensions and a first sub-field position within the exposure field,

wherein the first sub-field dimensions are different from the field dimensions; and

setting optical parameters of the projection exposure system to a setting wherein

the imaging performance within the first sub-field is a substantially optimum performance with regard to a first imaging characteristic, and

the imaging performance with regard to the first imaging characteristic is better within the first sub-field than within an area within the exposure field which is situated outside of the first sub-field.

29. A projection exposure system comprising an illumination optical system having a pupil plane and including a light source for illuminating a patterning structure and a projection optical system for imaging a region of the illuminated patterning structure into a corresponding field in a substrate-plane for exposing substrates with images of the patterning structure in a manufacturing process of miniaturized articles formed from the exposed substrates,

wherein the illumination optical system comprises

a first optical integrator system for illuminating a first region of a first size of the patterning structure, and

at least a second optical integrator system for illuminating a second region of the patterning structure which has a second size which is different from the first size wherein the first and at least second optical integrator are arranged such that the first optical integrator can be exchanged for the at least second optical integrator system, and

wherein a distribution of illumination intensity in a pupil plane of the illumination optical system in terms of shape and size is substantially the same for the first and at least second optical integrator system.

30. The projection exposure system of claim 29, wherein the first and at least second optical integrator system each comprise a diffractive or refractive optical raster element.

31. The projection exposure system of claim 30, wherein the first and at least second optical integrator system further each comprise a glass rod.

32. The projection exposure system of claim 29, wherein the first and at least second optical integrator system each comprise a fly'"'"'s eye condenser.