SENSOR ASSEMBLY AND METHOD FOR DETERMINING RESPECTIVE POSITIONS OF A NUMBER OF MIRRORS OF A LITHOGRAPHY SYSTEM

• US 20180067400A1
• Filed: 11/09/2017
• Published: 03/08/2018
• Est. Priority Date: 05/18/2015
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Inventors: Horn, Jan, Krone, Stefan, Berger, Lars
• Granted Patent: US 10,437,155 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01D 5/347 using displacement encoding scales
• 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 7/70825 Mounting of individual elements, e.g. mounts, holders or supports workpiece or mask holders G03F7/707
• 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

Abstract

Sensor arrangements, methods for ascertaining a respective position of a number of mirrors of a lithography apparatus, projection systems of a lithography apparatus, and lithography apparatus are disclosed. The sensor arrangement includes at least one position sensor apparatus for providing a position signal for a mirror and an evaluation apparatus for ascertaining the position of the mirror depending on the position signal.

Claims

1. A sensor arrangement, comprising:

a number of position sensor apparatuses, each position sensor apparatus comprising;

a measuring unit;

a light source to expose the measuring unit to a modulated light beam so that the measuring unit provides an optical position signal of a position of a mirror of a lithography apparatus during exposure by the modulated light beam; and

a detection unit comprising a plurality of photodetectors to output an electrical position signal by detection of the provided optical position signal; and

an evaluation apparatus configured to ascertain the position of the mirror via the electrical position signal,

wherein;

the measuring unit comprises;

a reference pattern to influence the light beam; and

a mirror arrangement for reflecting the influenced light beam;

the evaluation apparatus comprises a signal-processing unit comprising at least one A/D converter to convert an analog electrical position sensor output by the photodetector into a digital electrical position signal; and

the light source and the signal-processing unit are disposed in an integrated component arranged in a vacuum housing.

2. The sensor arrangement of claim 1, wherein the light source is configured to generate a pulsed light beam for exposing the measuring unit.

3. The sensor arrangement of claim 1, wherein the light source is configured to generate a sinusoidal light beam for exposing the measuring unit.

4. The sensor arrangement of claim 1, wherein the light source comprises:

a light-producing unit to produce a light beam; and

a modulator unit to generate the modulated light beam from the light beam produced by the light-producing unit.

5. The sensor arrangement of claim 4, wherein the light-producing unit comprises a semiconductor laser.

6. The sensor arrangement of claim 4, further comprising a synchronization device configured to synchronize the signal-processing unit and the light source, wherein the pulse generator comprises the synchronization device, and the pulse generator is configured to synchronize the signal-processing unit and the light source via the sequence of pulses.

7. The sensor arrangement of claim 1, wherein the light source comprises:

a light-producing unit to produce light beam; and

a pulse generator to actuate the light-producing unit via a sequence of pulses so that the light-producing unit outputs the modulated light beam.

8. The sensor arrangement of claim 1, further comprising a synchronization device configured to synchronize the signal-processing unit and the light source.

9. The sensor arrangement of claim 8, wherein:

the A/D converter comprises a sampling unit and a quantization unit; and

the synchronization device is configured to synchronize the sampling unit and the light source to generate the modulated light beam.

10. The sensor arrangement of claim 8, wherein:

the signal-processing unit comprises the A/D converter and a signal analysis unit disposed downstream of the A/D converter; and

the synchronization device is configured to synchronize the signal analysis unit and the light source to generate the modulated light beam.

11. The sensor arrangement of claim 10, wherein the A/D converter is configured to multiply sample the electrical position signal.

12. The sensor arrangement of claim 8, wherein:

the signal-processing unit comprises the A/D converter and a demodulator disposed upstream of the A/D converter; and

the synchronization device is configured to synchronize the demodulator and the light source to generate a sinusoidal light beam.

13. The sensor arrangement of claim 12, wherein the light source and the signal-processing unit are disposed in a single integrated component.

14. The sensor arrangement of claim 1, wherein the light source (203), the signal-processing unit (207) and the photodetectors (205) of the detection unit (204) are provided in the integrated component (200).

15. The sensor arrangement of claim 1, further comprising a control apparatus to control actuators which are configured to actuate actuatable mirrors of the lithography apparatus.

16. The sensor arrangement of claim 15, wherein the control apparatus comprises the evaluation apparatus.

17. The sensor arrangement of claim 1, wherein the detection unit further comprises an optical unit to image the optical position signal that is provided by the measuring unit onto the photosensors.

18. The sensor arrangement of claim 1, further comprising:

a plurality N3 of position sensor apparatuses in the vacuum housing, a respective position sensor apparatus being to one of a plurality N2 of actuatable mirrors of the lithography apparatus; and

a data collection device in the vacuum housing,

wherein;

the data collection device and the evaluation apparatus are connected via a data link;

the evaluation apparatus is disposed outside of the vacuum housing;

the evaluation apparatus is configured to collect N3 electrical position signals provided by the N3 position sensor apparatuses to form a digital collective signal; and

the evaluation unit is configured to transfer the digital collective signal to the evaluation apparatus via the data link.

19. The sensor arrangement of claim 18, wherein the data collection device and the evaluation apparatus are connected via a single data link.

20. The sensor arrangement of claim 18, wherein the data link is a unidirectional data link.

21. The sensor arrangement of claim 18, wherein the data link comprises:

a vacuum through-connection apparatus for a vacuum-suitable through-connection through the vacuum housing;

a first data line coupled between the data collection apparatus and the vacuum through-connection apparatus; and

a second data line coupled between the vacuum through-connection apparatus and the evaluation apparatus.

22. The sensor arrangement of claim 1, further comprising:

a plurality N3 of position sensor apparatuses disposed in the vacuum housing, a respective position sensor apparatus being assigned to one of a plurality N2 of actuatable mirrors of the lithography apparatus; and

a bus system in the vacuum housing,

wherein;

the bus system is connected to the evaluation apparatus;

the evaluation apparatus is disposed outside the vacuum housing; and

the bus system is configured to transfer the N3 electrical position signals provided by the N3 position sensor apparatuses to the evaluation apparatus.

23. The sensor arrangement of claim 22, further comprising a vacuum through-connection apparatus for a vacuum-suitable through-connection of the bus system through the vacuum housing.

24. The sensor arrangement of claim 23, wherein the bus system comprises a plurality of bus lines coupling the position sensor apparatuses, and the lines are connected to a connector bracket.

25. The sensor arrangement of claim 24, wherein the data link comprises first and second data lines, wherein the first data line is coupled between the connector bracket and the vacuum through-connection apparatus, and the second data line is coupled between the vacuum through-connection apparatus and the evaluation apparatus.

26. The sensor arrangement of claim 2, further comprising:

a plurality N3 of position sensor apparatuses disposed in the vacuum housing, a respective position sensor apparatus being assigned to one of a plurality N2 of actuatable mirrors of the lithography apparatus;

an information collection device in the vacuum housing; and

a cable connecting the information collection device to the evaluation apparatus,

wherein;

the evaluation apparatus is outside of the vacuum housing; and

the evaluation apparatus is configured to transfer the N3 electrical position signals provided by the N3 position sensor apparatuses in analog fashion via the cable using multiplexing or using frequency multiplexing.

27. The sensor arrangement of claim 3, further comprising:

a plurality N3 of position sensor apparatuses in the vacuum housing, a respective position sensor apparatus being assigned to one of a plurality N2 of actuatable mirrors of the lithography apparatus;

an information collection device in the vacuum housing; and

a cable connecting the collection device and the evaluation apparatus,

wherein the evaluation apparatus is outside the vacuum housing, and the evaluation device is configured to transfer the N3 electrical position signals provided by the N3 position sensor apparatuses in analog fashion via the cable using frequency multiplexing.

28. A projection system (104) of a lithography apparatus (100), comprising:

a plurality N1 of mirrors comprising N2 actuatable mirrors, where N2 being less than or equal to N1; and

a sensor arrangement according to claim 1,

wherein respectively a number N4 of the position sensor apparatuses are assigned to one of the N2 actuatable mirrors, and N3=N4·

N2.

29. The projection system of claim 28, further comprising:

a plurality of actuators to actuate the actuatable mirrors; and

a control apparatus to control the actuators.

30. The projection system of claim 29, wherein the control apparatus comprises the evaluation apparatus.

31. The projection system of claim 29, wherein the evaluation apparatus is configured to determine a respective position for each of the N2 actuatable mirrors depending on the respective electrical position signal.

33. The projection system of claim 28, further comprising a power supply apparatus to supply the sensor arrangement with electrical power.

34. A lithography apparatus, comprising:

a projection system, comprising;

a plurality N1 of mirrors comprising N2 actuatable mirrors, where N2 being less than or equal to N1; and

a sensor arrangement according to claim 1,

wherein respectively a number N4 of the position sensor apparatuses are assigned to one of the N2 actuatable mirrors, and N3=N4·

N2.

32. The projection system of 31, wherein the control apparatus is configured to actuate the actuators depending on the positions, deter-mined by the evaluation apparatus, of the actuatable mirrors.

35. A method, comprising:

exposing a measuring unit to modulated light beam;

using a detection unit having a plurality of photodetectors to detect an optical position signal that is provided by the measuring unit when exposed to the modulated light beam, for the output of an electrical position signal, the measuring unit having a reference pattern to influence the light beam and a mirror arrangement to reflect the influenced light beam; and

ascertaining the position of the mirror via the electrical position signal using an evaluation apparatus comprising a signal-processing unit comprising at least one A/D converter to convert an analog electrical position sensor output by the photodetector into a digital electrical position signal,

wherein at least the light source and the signal-processing unit are disposed in an integrated component in a vacuum housing.