APPARATUS FOR WAVEFRONT DETECTION
An arrangement for microlithography includes a projection objective having a plurality of optical elements; an aberration control circuit controlling imaging properties of the projection objective; and at least one operating element associated with an optical element of the projection objective to control imaging properties of the projection objective in response to operating signals generated by the control circuit.
1 . An arrangement for microlithography comprising:
a projection objective having a plurality of optical elements;
an aberration control circuit controlling imaging properties of the projection objective, the aberration control circuit including:
an apparatus for wavefront detection determining an instantaneous wavefront topography characteristic of the imaging properties of the projection objective; and
at least one operating element mechanically coupled to an optical element of the projection objective to control, by mechanical action on the coupled optical element, imaging properties of the projection objective in response to operating signals generated by the apparatus for wavefront detection.
2 . The arrangement according to claim 1 , wherein the at least one operating element is a positioning member configured to change the position of the coupled optical element relative to other ones of the optical elements of the projection objective.
3 . The arrangement according to claim 1 , wherein the at least one operating element is a positioning member configured to displace the coupled optical element of the projection objective.
4 . The arrangement according to claim 1 , wherein the at least one operating element is a positioning member configured to rotate the coupled optical element of the projection objective.
5 . The arrangement according to claim 1 , wherein the at least one operating element includes an actuator configured to deform the coupled optical element.
6 . The arrangement according to claim 1 , wherein the at least one operating element includes an actuator configured to apply mechanical stress to the coupled optical element.
7 . The arrangement according to claim 1 , wherein the optical element coupled to the at least one operating element is a lens of the projection objective.
8 . The arrangement according to claim 1 , wherein the projection objective has at least two of the operating elements, each coupled to a respective optical element and configured to control optical properties of the respective optical element.
9 . The arrangement according to claim 1 , wherein the aberration control circuit is configured as a closed loop circuit including a feedback loop.
10 . The arrangement according to claim 1 , wherein the aberration control circuit is configured as an open control circuit without a feedback loop.
11 . The arrangement according to claim 1 , wherein the aberration control circuit includes a comparator comparing signals emitted by the apparatus for wave-front detection and corresponding to a detected wavefront with a reference value that corresponds to a desired imaging property of the projection objective, and wherein the comparator emits signals controlling the at least one operating element.
12 . The arrangement according to claim 1 , wherein the apparatus for wavefront detection includes a diffraction grating.
13 . The arrangement according to claim 1 , wherein the apparatus for wavefront detection is an interferometer.
14 . The arrangement according to claim 1 , wherein the apparatus for wavefront detection comprises:
a wavefront source which produces a wavefront;
a diffraction grating following the wavefront source; and
a spatially resolving detector following the diffraction grating.
15 . The arrangement according to claim 14 , wherein the wavefront source is configured to move between a first position in an object plane of the projection objective and a second position that is removed from the object plane.
16 . The arrangement according to claim 1 , wherein the apparatus for wavefront detection is a multi-channel apparatus for wavefront detection configured to detect, in parallel, wavefronts from plural field points at a given instant in time.
17 . The arrangement according to claim 1 , wherein the arrangement for microlithography has an operating light source used in operation of the arrangement for microlithography and wherein the measuring system operates with the operating light source at an operating wavelength of the arrangement for microlithography.
18 . An arrangement for microlithography comprising:
a projection objective having a plurality of optical elements;
an aberration control circuit controlling imaging properties of the projection objective, the aberration control circuit including a measuring system configured to determine imaging properties of the projection objective; and
at least one operating element associated with an optical element of the projection objective to control imaging properties of the projection objective in response to operating signals generated by the measuring system;
wherein the measuring system is a multi-channel measuring system configured to measure imaging properties of the projection objective in parallel for plural field points at a given instant in time.
19 . The arrangement according to claim 18 , wherein the at least one operating element is a positioning member configured to change the position of the associated optical element relative to other optical elements of the projection objective.
20 . The arrangement according to claim 18 , wherein the measuring system includes a diffraction grating.
21 . The arrangement according to claim 18 , wherein the measuring system is an interferometer.
22 . The arrangement according to claim 18 , wherein the measuring system comprises:
a wavefront source which produces a wavefront;
a diffraction grating following the wavefront source; and
a spatially resolving detector following the diffraction grating.
23 . The arrangement according to claim 22 , wherein a plurality of wavefront sources are arranged in front of the diffraction grating.
24 . The arrangement according to claim 18 , wherein the arrangement for microlithography has an operating light source used in operation of the arrangement for microlithography and wherein the measuring system operates with the operating light source at an operating wavelength of the arrangement for microlithography.
25 . An arrangement for microlithography comprising:
a projection objective having a plurality of optical elements;
an aberration control circuit controlling imaging properties of the projection objective, the aberration control circuit including a measuring system configured to determine imaging properties of the projection objective; and
at least one operating element associated with an optical element of the projection objective to control imaging properties of the projection objective in response to operating signals generated by the measuring system;
wherein the measuring system includes a diffraction grating.
26 . The arrangement according to claim 25 , wherein the diffraction grating has a respective diffracting periodic structure in different periodicity directions.
27 . The arrangement according to claim 26 , wherein the diffraction grating has two mutually orthogonal periodicity directions.
28 . The arrangement according to claim 25 , wherein the measuring system is an interferometer.
29 . The arrangement according to claim 28 , wherein the measuring system is a lateral shearing interferometer, where a lateral shearing of wavefronts is caused by the diffraction grating.
30 . The arrangement according to claim 25 , wherein the measuring system comprises:
a wavefront source which produces a wavefront;
the diffraction grating following the wavefront source; and
a spatially resolving detector following the diffraction grating.
31 . The arrangement according to claim 30 , wherein a plurality of wavefront sources are arranged in front of the diffraction grating.
32 . The arrangement according to claim 25 , wherein the arrangement for microlithography has an operating light source used in operation of the arrangement for microlithography and wherein the measuring system operates with the operating light source at an operating wavelength of the arrangement for microlithography.
33 . An arrangement for microlithography comprising:
a projection objective having a plurality of optical elements;
an aberration control circuit controlling imaging properties of the projection objective, the aberration control circuit including a measuring system configured to determine imaging properties of the projection objective; and
at least one operating element associated with an optical element of the projection objective to control imaging properties of the projection objective in response to operating signals generated by the measuring system;
wherein the arrangement for microlithography has an operating light source used in operation of the arrangement for microlithography and wherein the measuring system operates with the operating light source at an operating wavelength of the arrangement for microlithography.
34 . The arrangement according to claim 33 , wherein the operating light source is an excimer laser.
35 . The arrangement according to claim 33 , wherein the operating light source is a synchrotron radiator.
36 . The arrangement according to claim 33 , wherein the measuring system includes a diffraction grating.
37 . The arrangement according to claim 33 , wherein the measuring system is an interferometer.
38 . The arrangement according to claim 33 , wherein the measuring system comprises:
a wavefront source which produces a wavefront;
a diffraction grating following the wavefront source; and
a spatially resolving detector following the diffraction grating.