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

• US 20180067399A1
• Filed: 11/08/2017
• 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 10,444,633 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: 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

A 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 configured to ascertain a respective position of a number of mirrors of a lithography apparatus, the sensor arrangement comprising:

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

a measuring unit to provide an optical position signal of a position of a mirror in the case of exposure by a light beam;

a light source to expose the measuring unit to the light beam;

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

a signal-processing unit comprising an A/D converter to convert the analog electrical position signal into a digital electrical position signal, the light source and the signal-processing unit being provided in an integrated component arranged in a vacuum housing; and

an evaluation apparatus to ascertain the position of the mirror via the digital electrical position signal.

2. The sensor arrangement of claim 1, wherein the light source and the signal-processing unit are provided in a single integrated component.

3. The sensor arrangement of claim 1, wherein the light source, the signal-processing unit and the photodetectors are provided in the integrated component.

4. 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 photodetectors.

5. The sensor arrangement of claim 1, wherein:

a plurality N3 of position sensor apparatuses are arranged in the vacuum housing;

a respective position sensor apparatus is assigned to one of a plurality N2 of actuatable mirrors of the lithography apparatus;

a data collection apparatus is arranged in the vacuum housing;

the data collection apparatus is connected by way of a data link to the evaluation apparatus outside of the vacuum housing; and

the data collection apparatus is configured to bring together or combine the N3 digital electrical position signals provided by the N3 position sensor apparatuses to form a digital collective signal and to transfer the digital collective signal to the evaluation apparatus via the data link.

6. The sensor arrangement of claim 5, wherein the data collection apparatus and the evaluation apparatus are connected via a single data link.

7. The sensor arrangement of claim 5, wherein the data link between the data collection apparatus and the evaluation apparatus is a unidirectional data link.

8. The sensor arrangement of claim 5, wherein the data link has a vacuum through-connection apparatus for a vacuum-suitable through-connection through the vacuum housing, a first data line is coupled between the data collection apparatus and the vacuum through-connection apparatus, and a second data line is coupled between the vacuum through-connection apparatus and the evaluation apparatus.

9. The sensor arrangement of claim 5, wherein the data collection apparatus is connected to each one of the N3 position sensor apparatuses via a respective line.

10. The sensor arrangement of claim 9, wherein a connector bracket electrically couples the data collection apparatus and the first data line.

11. The sensor arrangement of claim 1, wherein:

a plurality N3 of position sensor apparatuses are arranged in the vacuum housing;

a respective position sensor apparatus is assigned to one of a plurality N2 of actuatable mirrors of the lithography apparatus;

a bus system is at least partly arranged in the vacuum housing;

the bus system is connected to the evaluation apparatus that is arranged outside of the vacuum housing; and

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

12. The sensor arrangement of claim 11, further comprising a vacuum through-connection apparatus for a vacuum-suitable through-connection of the bus system through the vacuum housing.

13. The sensor arrangement of claim 12, wherein the bus system comprises a plurality of bus lines coupling the position sensor apparatuses, and the bus lines are connected to a connector bracket.

14. The sensor arrangement of claim 13, wherein the data link has a first data line coupled between the connector bracket and the vacuum through-connection apparatus, and the data link has a second data line coupled between the vacuum through-connection apparatus and the evaluation apparatus.

15. The sensor arrangement of claim 1, wherein the measuring unit has a reference pattern to influence the light beam and a mirror arrangement for reflecting the influenced light beam.

16. The sensor arrangement of claim 15, wherein the reference pattern is between the light source and the mirror arrangement.

17. The sensor arrangement of claim 15, wherein the reference pattern has a scale, in particular a holographic scale.

18. The sensor arrangement of claim 1, wherein the light source is configured to expose the measuring unit with a modulated light beam.

19. The sensor arrangement of claim 18, wherein the light source is configured to generate a pulsed light beam to expose the measuring unit.

20. The sensor arrangement of claim 18, wherein the light source is configured to generate a sinusoidal light beam to expose the measuring unit.

21. The sensor arrangement of claim 18, wherein the light source comprises a light-producing unit to produce a light beam, and the light source comprises a modulator unit to generate a modulated light beam from the light beam produced by the light-producing unit.

22. The sensor arrangement of claim 18, wherein the light source comprises a light-producing unit to produce a light beam, and the light source comprises a pulse generator configured to actuate the light-producing unit via a sequence of pulses so that the light-producing unit outputs the modulated light beam.

23. The sensor arrangement of claim 21, wherein the light-producing unit comprises a semiconductor laser.

24. A lithography projection system, comprising:

a plurality N1 of mirrors comprising a number N2 of actuatable mirrors, where N2≦

N1; and

a sensor arrangement according to claim 1, wherein the sensor arrangement comprises a plurality N3 of position sensor apparatuses, a number N4 of the position sensor apparatuses are assigned to one of the N2 actuatable mirrors, where N3=N4·

N2.

25. The projection system of claim 24, further comprising a plurality of actuators for actuating the actuatable mirrors, and a control apparatus to control the actuators.

26. The projection system of claim 25, wherein the control apparatus comprises the evaluation apparatus.

27. The projection system of claim 25, wherein the evaluation apparatus is configured to determine a respective position for each of the N2 actuatable mirrors depending on the respective digital electrical position signal.

28. The projection system of claim 27, wherein the control apparatus is configured to regulate the actuators depending on the positions, determined by the evaluation apparatus, of the actuatable mirrors.

29. The projection system of claim 24, further comprising a power supply apparatus to supply the sensor arrangement arranged in the vacuum housing with electrical power.

30. A lithography apparatus, comprising:

a projection system which comprises;

a plurality N1 of mirrors comprising a number N2 of actuatable mirrors, where N2≦

N1; and

a sensor arrangement according to claim 1,

wherein the sensor arrangement comprises a plurality N3 of position sensor apparatuses, a number N4 of the position sensor apparatuses are assigned to one of the N2 actuatable mirrors, where N3=N4·

N2.

31. A method of ascertaining a respective position of a number of mirrors of a lithography apparatus, the method comprising:

a) exposing a measuring unit to a light beam;

b) detecting an optical position signal, provided by the measuring unit, by a detection unit for outputting an analog electrical position sig-nal;

c) converting the analog electrical position signal into a digital electrical position signal by an A/D converter, a) to c) being performed by an integrated component arranged in a vacuum housing, integrating the light source, the detection unit and the A/D converter; and

d) ascertaining the position of the mirror via the digital electrical position signal.