Control device for controlling at least one manipulator of a projection lens

Patent metadata

Field	Value
Publication number	US-9823578-B2
Application number	US-201615081074-A
Country	US
Kind code	B2
Filing date	Mar 25, 2016
Priority date	Apr 10, 2015
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

The disclosure provides a control device for controlling at least one manipulator of a microlithographic projection lens by generating a travel command, which defines a change to be undertaken, of an optical effect of at least one optical element of the projection lens by manipulating a property of the optical element via the at least one manipulator along a travel. The control device is configured to generate the travel command for the at least one manipulator from a state characterization of the projection lens by optimizing a merit function. Here, the merit function includes a linear combination of at least two exponential expressions, a setting of the at least one manipulator defining the manipulation of the property of the optical element is represented via a travel variable and the respective base of the at least two exponential expressions contains a function of the travel variable.

First claim

What is claimed is:

1. A control device, wherein:
the control device is configured to control a manipulator of a microlithographic projection lens by generating a travel command;
the travel command defines a change to be undertaken of an optical effect of an optical element of the microlithographic projection lens by manipulating a property of the optical element via the manipulator along a travel;
the control device is configured to generate the travel command for the manipulator from a state characterization of the microlithographic projection lens by optimizing a merit function;
the merit function comprises a linear combination of at least two exponential expressions;
a setting of the manipulator defines the manipulation of the property of the optical element is represented via a travel variable and a respective base of the at least two exponential expressions contains a function of the travel variable; and
exponents of the at least two exponential expressions have different values.

2. The control device of claim 1 , wherein the at least two exponential expressions have different bases.

3. The control device of claim 1 , wherein each of the exponents of the at least two exponential expressions has a value of at least two.

4. The control device of claim 1 , wherein, for each base of the at least two exponential expressions:
the base comprises a quotient comprising a numerator and a denominator;
the numerator of the base comprises a term comprising the function of the travel variable; and
the denominator of the base comprises a target value for the term of the numerator and a weighting factor for the target value.

5. The control device of claim 1 , wherein a difference in the values of the at least two exponents is at least five.

6. The control device of claim 1 , wherein:
the control device is configured to control a plurality of manipulators;
the state characterization comprises a plurality of state parameters characterized by a state vector; and
each of the exponential expressions comprises a sensitivity matrix defining a relationship between the travels of the manipulators and the state vector.

7. The control device of claim 1 , wherein one of the exponential expressions comprises a term which describes an image aberration of the microlithographic projection lens.

8. The control device of claim 1 , wherein one of the exponential expression comprises a term which describes a fading aberration of a microlithographic step-and-scan projection exposure apparatus.

9. The control device of claim 1 , wherein one of the exponential expression comprises a term which describes a root mean square of a selection of image aberrations of the microlithographic projection lens.

10. The control device of claim 1 , wherein one of the exponential expression comprises a term which describes a pure overlay error.

11. The control device of claim 1 , wherein one of the exponential expressions includes a term which describes an error correctable by means of mechanical post-processing of an optical element of the microlithographic projection lens.

12. The control device of claim 1 , wherein the merit function contains at least one implicit constraint for the travel.

13. An adjustment apparatus, the adjustment apparatus comprising:
a measurement system; and
a control device according to claim 1 ,
wherein:
the adjustment apparatus is configured to adjust the microlithographic projection lens; and
the measurement system is configured to establish the state characterization of the microlithographic projection lens.

14. The adjustment apparatus of claim 13 , wherein the measurement system comprises a wavefront measurement device.

15. An apparatus, comprising:
a control device according to claim 1 ; and
the microlithographic projection lens.

16. The apparatus of claim 15 , further comprising an illumination device configured to provide radiation to the microlithographic projection lens.

17. The apparatus of claim 15 , further comprising a measurement system configured establish the state characterization of the microlithographic projection lens.

18. An apparatus, comprising:
an illumination optical unit configured to illuminate an object plane;
a projection lens configured to image the object plane into an image plane; and
a control device,
wherein:
the projection lens comprises an optical element and a manipulator;
the control device is configured to control the manipulator by generating a travel command;
the travel command defines a change to be undertaken of an optical effect of the optical element by manipulating a property of the optical element via the manipulator along a travel;
the control device is configured to generate the travel command for the manipulator from a state characterization of the projection lens by optimizing a merit function;
the merit function comprises a linear combination of at least two exponential expressions;
a setting of the manipulator defining the manipulation of the property of the optical element is represented via a travel variable and a respective base of the at least two exponential expressions contains a function of the travel variable; and
exponents of the at least two exponential expressions have different values.

19. The apparatus of claim 18 , further comprising a measurement system configured establish the state characterization of the microlithographic projection lens.

20. A method of controlling a manipulator of a microlithographic projection lens, the method comprising:
generating a travel command for the manipulator by carrying out an optimization of a merit function, wherein:
the merit function comprises a linear combination of at least two exponential expressions;
a setting of the manipulator defines a manipulation of a property of an optical element of the microlithographic projection lens is represented via a travel variable, and a respective base of the at least two exponential expressions contains a function of the travel variable; and
exponents of the at least two exponential expressions have different values; and

manipulating the property of the optical element via the manipulator along the travel variable defined by the generated travel command to change an optical effect of the optical element of the microlithographic projection lens.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Rist Stefan

Classifications

• G03F7/70258 Primary

  Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system · CPC title

• G03F7/70433

  Layout for increasing efficiency or for compensating imaging errors, e.g. layout of exposure fields for reducing focus errors; Use of mask features for increasing efficiency or for compensating imaging errors · CPC title

• G03F7/70266 Primary

  Adaptive optics, e.g. deformable optical elements for wavefront control, e.g. for aberration adjustment or correction · CPC title

• G03F7/705

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title

• G02B27/0012

  Optical design, e.g. procedures, algorithms, optimisation routines · CPC title