Projection objective including an optical device

Patent metadata

Field	Value
Publication number	US-12411417-B2
Application number	US-202318153640-A
Country	US
Kind code	B2
Filing date	Jan 12, 2023
Priority date	Jul 30, 2020
Publication date	Sep 9, 2025
Grant date	Sep 9, 2025

Abstract

A projection exposure apparatus comprises a projection objective, and the projection objective comprises an optical device, wherein the optical device comprises an optical element having an optically effective surface and an electrostrictive actuator. The electrostrictive actuator is deformable by a control voltage being applied. The electrostrictive actuator is functionally connected to the optical element to influence the surface shape of the optically effective surface. A control device supplies the electrostrictive actuator with the control voltage. A measuring device is configured, at least at times while the electrostrictive actuator influences the optically effective surface of the optical element, to measure directly and/or to determine indirectly the temperature and/or a temperature change of the electrostrictive actuator and/or the surroundings thereof to take account of a temperature-dependent influence during driving of the electrostrictive actuator by the control device.

First claim

What is claimed is:

1. An apparatus, comprising:
a projection objective, comprising:
an optical device;
a controller; and
temperature sensors,

wherein:
the optical device comprises an optical element and an electrostrictive actuator;
the optical element comprises an optically effective surface;
the optical element is adjacent an intermediate image plane of the apparatus;
the controller is configured to provide a control voltage to the electrostrictive actuator to deform the electrostrictive actuator;
the electrostrictive actuator is connected to the optical element to influence a surface shape of the optically effective surface;
the temperature sensors are configured to measure: a) a temperature of the electrostrictive actuator; b) a temperature change of the electrostrictive actuator; c) a temperature distribution of the electrostrictive actuator; d) and/or a temperature distribution of surroundings of the electrostrictive actuator;
the temperature sensors are configured so that, at least at times when the electrostrictive actuator influences the optically effective surface of the optical element, the temperature sensors determine: a) the temperature of the electrostrictive actuator; b) the temperature change of the electrostrictive actuator; and/or c) a temperature of the surroundings the electrostrictive actuator, thereby taking account of a temperature-dependent influence when the electrostrictive actuator is driven by the control device; and
the apparatus is a projection exposure apparatus.

2. The apparatus of in claim 1 , wherein the temperature sensors are configured to directly measure a) the temperature of the electrostrictive actuator; b) the temperature change of the electrostrictive actuator; and/or c) the temperature of the surroundings the electrostrictive actuator.

3. The apparatus of in claim 1 , wherein the temperature sensors are configured to indirectly determine a) the temperature of the electrostrictive actuator; b) the temperature change of the electrostrictive actuator; and/or c) the temperature of the surroundings the electrostrictive actuator.

4. The apparatus of in claim 1 , wherein the temperature sensors are configured to measure at least one of the following variables to indirectly determine the temperature and/or the temperature change:
temperature-dependent properties of the electrostrictive actuator;
a change of the surface shape of the optically effective surface; and
a change of a surface shape of a surface of the optical element other than the optically effective surface.

5. The apparatus of in claim 1 , wherein the temperature sensors are configured to continuously measure and/or to continuously determine the temperature and/or the temperature change during use of the electrostrictive actuator.

6. The apparatus of in claim 1 , wherein the electrostrictive actuator is configured so that, when the control voltage is applied to electrostrictive actuator, electrostrictive actuator undergoes a lateral deformation in a plane of the electrostrictive actuator.

7. The apparatus of in claim 1 , wherein the control device is configured so that, based on data ascertained by the temperature sensors, the control device adapts a value for an m31-or d31-coefficient which characterizes a transverse electrostrictive effect, to drive the electrostrictive actuator to take account of a temperature-dependent influence.

8. The apparatus of in claim 1 , wherein the control device is configured to take account of thermal changes of material parameters within the electrostrictive actuator and/or of components in the surroundings of the electrostrictive actuator.

9. The apparatus of in claim 1 , further comprising an adhesive or a soldered connection securing the electrostrictive actuator to the optical element, wherein the control device is configured to take account of a thermal change in the stiffness and/or an expansion of the adhesive or the soldered connection when the electrostrictive actuator is driven.

10. The apparatus of in claim 1 , wherein the electrostrictive actuator is at a rear side of the optical element, and the rear side faces away from the optically effective surface.

11. The apparatus of in claim 1 , wherein the electrostrictive actuator is on the optically effective surface outside a light region, or the electrostrictive actuator is on a side surface of the optical element.

12. The apparatus of in claim 1 , wherein the electrostrictive actuator comprises a plurality of electrostrictive components.

13. The apparatus of in claim 1 , wherein the temperature sensors are configured to measure a capacitance and/or an electrical resistance and/or a frequency-dependent impedance of the electrostrictive actuator to determine the temperature and/or the temperature change.

14. The apparatus of in claim 1 , wherein the temperature sensors comprise an infrared camera configured to detect temperature, and/or wherein the temperature sensors comprise an electrical bridge circuit configured to measure temperature-dependent properties of the electrostrictive actuator.

15. The apparatus of in claim 1 , wherein the temperature sensors are at a rear side ( 3 a ) of the electrostrictive actuator, and the rear side faces away from the optically effective surface.

16. The apparatus of in claim 1 , wherein the electrostrictive actuator comprises electrostrictive components at a side of the optical element, and the temperature sensors are between the electrostrictive components.

17. The apparatus of in claim 1 , wherein the temperature sensors are configured to measure a temperature change of 0.1 K or greater.

18. The apparatus of in claim 1 , further comprising:
first supply lines configured to supply the control voltage to the electrostrictive actuator; and
second supply lines configured to provide an operating voltage to the temperature sensors.

19. The apparatus of in claim 1 , wherein:
the control device is configured so that, based on data from the temperature sensors, the control device ascertains an expected wavefront effect due to the change in the surface shape and/or a change in a refractive index of the optical element; and
the control device is configured to take account of the wavefront effect when driving the electrostrictive actuator, and/or the control device is configured to take account of a compensation mechanism.

20. The apparatus of claim 1 , wherein the temperature sensors are configured so that data collected by the temperature sensors is usable to determine a parasitic effect on the surface shape of the optically effective surface and/or to determine a change in a refractive index of the optical element.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Lippert Johannes
• Gruner Toralf
• Hild Kerstin
• Stiepan Hans Michael
• Pollak Thilo
• Cavaco Jeffrey

Classifications

• G03F7/70891

  Temperature · CPC title

• G02B26/0825

  the reflecting element being a flexible sheet or membrane, e.g. for varying the focus (flexible mirrors for cosmetic use A45D42/24) · CPC title

• G02B13/16

  for use in conjunction with image converters or intensifiers {, or for use with projectors, e.g. objectives for projection TV} · CPC title

• H10N30/206

  using only longitudinal or thickness displacement, e.g. d33 or d31 type devices · CPC title

• H10N30/802

  Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits · CPC title