ILLUMINATION SYSTEM FOR EUV LITHOGRAPHY
The disclosure relates to an illumination system for EUV lithography, as well as related elements, systems and methods. In some embodiments, an illumination system includes a first optical element and a second optical element. The first optical element can include a plurality of first facet elements configured so that, when impinged by respective partial beams of radiation, the plurality of first facet elements produce secondary light sources. The second optical element can include a second optical element including a plurality of second facet elements. Each of the plurality of second facet elements can be assigned to at least one of the plurality of first facet elements. The plurality of second facet elements can be configured to be impinged by the radiation via the first optical element.
1 . An illumination system configured to illuminate an illumination field of an object surface with radiation, the illumination system comprising:
a first optical element comprising a plurality of first facet elements configured so that, when impinged by respective partial beams of the radiation, the plurality of first facet elements produce secondary light sources; and
an optical arrangement configured to image the first optical element into the illumination field, the optical arrangement comprising:
a second optical element comprising a plurality of second facet elements, each of the plurality of second facet elements being assigned to at least one of the plurality of first facet elements, the plurality of second facet elements configured to be impinged by the radiation via the first optical element,
wherein the illumination field includes at least first and second partial fields, at least two of the plurality of first facet elements are configured to be imaged by the optical arrangement into the first partial field of the illumination field, and the illumination system is configured to be used in EUV lithography.
2 . The illumination system of claim 1 , wherein there is no intersection between the first and second partial fields.
3 . The illumination system of claim 1 , wherein there is an intersection between the first and second partial fields that is smaller than both the first and second partial fields.
4 . The illumination system according to claim 3 , wherein the intersection between the first and second partial fields is less than 95% of the first partial field, and the intersection between the first and second partial fields is less than 95% of the second partial field.
5 . The illumination system according to claim 3 , wherein the intersection between the first and second partial fields is less than 90% of the first partial field, and the intersection between the first and second partial fields is less than 90% of the second partial field.
6 . An illumination system according to claim 3 , wherein the intersection between the first and second partial fields is less than 80% of the first partial field, and the intersection between the first and second partial fields is less than 80% of the second partial field.
7 . An illumination system according to claim 3 , wherein the intersection between the first and second partial fields is less than 60% of the first partial field, and the intersection between the first and second partial fields is less than 60% of the second partial field.
8 . An illumination system according to claim 3 , wherein the intersection between the first and second partial fields is less than 40% of the first partial field, and the intersection between the first and second partial fields is less than 40% of the second partial field.
9 . An illumination system according to claim 3 , wherein the intersection between the first and second partial fields is less than 20% of the first partial field, and the intersection between the first and second partial fields is less than 20% of the second partial field.
10 . The illumination system according to claim 1 , further comprising actuators configured to move at least some of the first facet elements between setting positions so that in each setting position the corresponding partial beam of radiation is deflected by the first facet element, wherein at least one of the second facet elements is configured to be acted on by at least two different first facet elements.
11 . The illumination system according to claim 1 , wherein a number of partial fields of the illumination field corresponds to a maximum number of first facet elements which are able to act on the same second facet element.
12 . The illumination system according to claim 1 , wherein the first and second partial fields are adjacent partial field strips.
13 . The illumination system according to claim 12 , wherein the first and second partial fields have the same surface area.
14 . The illumination system according to claim 13 , wherein at least one member is curved, the at least one member being selected from the group consisting of the plurality of first facets elements and the first and second partial fields.
15 . The illumination system according to claim 1 , wherein at least one of the plurality of second facet elements is configured to be acted on by precisely two adjacent first facet elements.
16 . The illumination system according to claim 1 , further comprising actuators configured to displace at least one of the second facet elements between first and second positions.
17 . The illumination system according to claim 1 , wherein at least one member comprises reflective elements, the at least one member being selected from the group consisting of the plurality of first facet elements and the plurality of second facet elements.
18 . The illumination system according to claim 1 , wherein the number of the first facet elements is identical to the number of the second facet elements.
19 . An illumination system configured to illuminate an illumination field of an object surface with radiation, the illumination system comprising:
a first optical element comprising a plurality of first facet elements configured so that, when impinged by respective partial beams of the radiation, the plurality of first facet elements produce secondary light sources; and
an optical arrangement configured to image the first optical element into the illumination field, the optical arrangement comprising:
a second optical element comprising a plurality of second facet elements, each of the plurality of second facet elements being assigned to at least one of the plurality of first facet elements, the plurality of second facet elements configured to be impinged by the radiation via the first optical element,
wherein at least two of the first facet elements are configured to be imaged into the illumination field via one of the plurality of second facet elements, and the illumination system is configured to be used in EUV lithography.
20 . An illumination system configured to illuminate an illumination field of an object surface with radiation, the illumination system comprising:
a plurality of first facet elements configured to produce secondary light sources when impacted by the radiation; and
a plurality of second facet elements,
wherein the illumination system is configured to be used in EUV lithography, and during use an illumination setting:
determines a selection of the second facet elements used to illuminate the illumination field; and
an assignment of at least one corresponding first facet element to each of the second facet elements used to illuminate the illumination field so that only a part of the illumination field is illuminated by the at least one corresponding first facet element.
21 . The illumination system according to claim 20 , wherein the illumination system is configured so that the assignment of the at least one corresponding first facet element to each of the second facet elements used to illuminate the illumination field can be modified if the illumination setting is modified.
22 . The illumination system according to claim 21 , wherein the illumination system is configured so that so that the assignment of the at least one corresponding first facet element to each of the second facet elements used to illuminate the illumination field can be modified without any loss of radiation.