EXPOSURE APPARATUS AND MEASURING DEVICE FOR A PROJECTION LENS

• US 20100141912A1
• Filed: 02/09/2010
• Published: 06/10/2010
• Est. Priority Date: 01/20/2004
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Inventors: Ehrmann, Albrecht, Hoch, Rainer, Mallmann, Joerg, Wegmann, Ulrich, Geuppert, Bernhard, Gruner, Toralf, Sorg, Franz, Schuster, Karl-Heinz, Wabra, Norbert, Loering, Ulrich, Kugler, Jens, Kneer, Bernhard
• Granted Patent: US 8,330,935 B2
• Time in Patent Office: Days
• US Class Current: 355/30
• 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 7/70591 Testing optical components
• CPC Class Codes: G03F 7/70691 Handling of masks or workpieces
• CPC Class Codes: G03F 7/7085 Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
• CPC Class Codes: G03F 7/70875 Temperature, e.g. temperature control of masks or workpieces via control of stage temperature
• CPC Class Codes: G03F 7/70891 Temperature
• CPC Class Codes: G03F 7/70991 Connection with other apparatus, e.g. multiple exposure stations, particular arrangement of exposure apparatus and pre-exposure and/or post-exposure apparatus; Shared apparatus, e.g. having shared radiation source, shared mask or workpiece stage, shared base-plate; Utilities, e.g. cable, pipe or wireless arrangements for data, power, fluids or vacuum

Abstract

A microlithographic projection exposure apparatus includes a projection lens that is configured for immersion operation. For this purpose an immersion liquid is introduced into an immersion space that is located between a last lens of the projection lens on the image side and a photosensitive layer to be exposed. To reduce fluctuations of refractive index resulting from temperature gradients occurring within the immersion liquid, the projection exposure apparatus includes heat transfer elements that heat or cool partial volumes of the immersion liquid so as to achieve an at least substantially homogenous or at least substantially rotationally symmetric temperature distribution within the immersion liquid.

Claims

1. An optical system, comprising:

an illumination system configured to generate projection light;

a projection lens configured to image a mask onto a photosensitive layer, an immersion space being between the projection lens and the photosensitive layer;

an immersion liquid in the immersion space, at least a portion of the immersion liquid being in direct contact with the projection lens and the photosensitive layer to form a boundary surface to a surrounding gas;

a heat transfer element configured to transfer an amount of heat to or from the portion of the immersion liquid; and

a control device configured to adjust the amount of heat transferred by the heat transfer element to or from the portion of the immersion liquid,

wherein the optical system is a microlithographic projection exposure apparatus.

2. The optical system of claim 1, wherein the heat transfer element is arranged in the immersion space so that the heat transfer element is in contact with the immersion liquid during an immersion operation.

3. The optical system of claim 2, wherein the heat transfer element comprises a heating wire.

4. The optical system of claim 1, wherein the immersion space is laterally delimited by a wall in which the heat transfer element is arranged.

5. The optical system of claim 1, wherein the heat transfer element comprises a Peltier element.

6. The optical system of claim 1, wherein the heat transfer element is arranged at a distance from the immersion space so that heat can be exchanged by thermal radiation between the heat transfer element and the portion of the immersion liquid.

7. The optical system of claim 6, further comprising a directive optical element configured to change a direction of the thermal radiation, the directive optical element being between the heat transfer element and the immersion space.

8. The optical system of claim 7, wherein the directive optical element has a positive refractive power.

9. The optical system of claim 6, wherein the heat transfer element comprises a planar radiator configured to be heated or cooled.

10. The optical system of claim 6, further comprising a thermal sensor configured to measure a temperature of the heat transfer element, wherein the thermal sensor is connected to the control device.

11. The optical system of claim 1, wherein the heat transfer element is configured to transfer the amount of heat via thermal radiation or thermal conduction.

12. The optical system of claim 1, wherein the heat transfer element is arranged in a wafer stage configured to position a carrier on which the photosensitive layer is applied.

13. The optical system of claim 12, wherein the heat transfer element has substantially the same symmetry as a light field that is illuminated on the photosensitive layer during use of the optical system.

14. The optical system of claim 12, wherein the heat transfer element comprises a plurality of conduits contained in the wafer stage to conduct a heating or cooling medium through the wafer stage.

15. The optical system of claim 1, wherein the control device is configured to adjust the amount of heat such that the temperature distribution of the immersion liquid is at least substantially homogenous or at least substantially rotationally symmetric.

16. An optical system, comprising:

an illumination system configured to generate projection light;

a projection lens configured to image a mask on a photosensitive layer;

an outlet configured to supply an immersion liquid so that immersion liquid that flows out of the outlet becomes in direct contact with the projection lens and the photosensitive layer to form a boundary surface to a surrounding gas;

a heat transfer element configured to transfer an amount of heat to or from the immersion liquid; and

a control device configured to adjust the amount of heat transferred by the heat transfer element to or from the portion of the immersion liquid,

wherein the optical system is a microlithographic projection exposure apparatus.

17. The optical system of claim 16, wherein the system comprises a plurality of outlets configured to supply immersion liquid so that immersion liquid that flows out of the outlets becomes in direct contact with the projection lens and the photosensitive layer to form a boundary surface to a surrounding gas, and wherein the control device is configured to control at least one outlet property independently for each of the plurality of outlets.

18. The optical system of claim 17, wherein the outlet property is the volume of immersion liquid that flows out of an outlet per unit time.

19. The optical system of claim 17 wherein the outlet property is the temperature of immersion liquid that flows out of an outlet.

20. The optical system of claim 19, wherein each outlet comprises heating and/or cooling elements arranged within a wall of the outlet.

21. The optical system of claim 16, wherein the control device is configured to adjust the amount of heat such that the temperature distribution of the immersion liquid that flows out of the at least one outlet is at least substantially homogenous or at least substantially rotationally symmetric.

22. An optical system, comprising:

an illumination system configured to generate projection light;

a projection lens configured to image a mask on a photosensitive layer;

a plurality of outlets configured to supply an immersion liquid such that immersion liquid that flows out of the plurality of outlets becomes in direct contact with the projection lens and the photosensitive layer to form a boundary surface to a surrounding gas; and

a control device configured to adjust the temperature of the immersion liquid that flows out of the outlets individually for at least two of the plurality of outlets,

wherein the optical system is a microlithographic projection exposure apparatus.

23. The optical system of claim 22, wherein the control device is configured to adjust the temperature of the immersion liquid flowing out of the outlets such that the immersion liquid flowed out of the outlets has a temperature distribution which is at least substantially homogenous or at least substantially rotationally symmetric.

24. The optical system of claim 22, comprising a temperature sensor that is configured to measure the temperature of the immersion liquid flowed out of the outlets.

25. The optical system of claim 24, wherein the control device is configured to adjust the temperature of the immersion liquid flowing out of the outlets such that the temperature measured by the temperature sensor is constant.