A system includes a plate configured for mounting of a reflective extreme ultra-violet (EUV) mask thereon and a zone plate configured to divide EUV light into zero-order light and first-order light and to pass the zero-order light and the first-order light to the reflective EUV mask. The system further includes a detector configured to receive EUV light reflected by the EUV mask and including a zero-order light detection region configured to generate a first image signal and a first-order light detection region configured to generate a second image signal, and a calculator configured to generate a compensated third image signal from the first image signal and the second image signal. The third image signal may be used to determine a distance between mask patterns of the EUV mask.

A method for aligning a mirror of a microlithographic projection exposure apparatus, according to one formulation, involves: recording a first partial interferogram between a wave reflected at a first mirror segment (101) and a reference wave reflected at a reference surface (110, 310, 510), recording a second partial interferogram between a wave reflected at a second mirror segment (102) and a reference wave reflected at the reference surface, determining a phase offset between the first partial interferogram and the second partial interferogram, and aligning the first mirror segment and the second mirror segment in relation to one another in accordance with the determined phase offset, so that the distance of the relevant mirror segments (101, 102) from a respective predetermined, hypothetical surface in the direction of the respective surface normal is less than /10 at each point on the mirror segments, where denotes the operating wavelength of the mirror.

An optical element for a projection exposure apparatus comprises a mirror body having an optically active surface. The mirror body comprises a base portion which carries a sensor system. The mirror body comprises an edge portion on which actuator connectors for connecting actuators to the optical element are provided. The base portion has greater stiffness than the edge portion. A stiffening rib structure is attached to the back side of the edge portion, which faces away from the optically active surface. The rib structure supports the edge portion on the base portion.

An imaging optical unit for projection lithography has a plurality of mirrors for guiding imaging light from an object field into an image field. The object field is spanned by a first, larger object field dimension and along a second, smaller object field dimension. The imaging optical unit has at least two GI mirrors and at least one NI mirror. The NI mirror is arranged between two GI mirrors in the imaging light beam path. A used reflection surface of the NI mirror has an aspect ratio between a surface dimension along a first reflection surface coordinate and a surface dimension along a second reflection coordinate parallel to the second object field dimension. The aspect ratio being less than 4.5. An imaging optical unit with reduced production costs emerges.

A projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.

An EUV lithography system (1) including: a housing (26), at least one reflective optical element (M1, M2) disposed within an interior (27) of the housing (26), and at least one gas-binding component (31a-c) having a gas-binding material for binding gaseous contaminating substances (29) present in the interior (27). The gas-binding component is formed as a foil (31a-c) and a coating (33, 33a,b) containing the gas-binding material is applied on at least one side (32a, 32b) of the foil (31a-c).

This disclosure relates to a method for producing a mirror of a microlithographic projection exposure apparatus, a first mirror part and a second mirror part being provided, which are in contact in the region of a first connecting surface of the first mirror part and a second connecting surface of the second mirror part. For forming a durable connection between the first mirror part and the second mirror part, the first mirror part and the second mirror part are heated up to a holding temperature of at least 400? C. and are kept at the holding temperature during a holding time. After the holding time has elapsed, the first mirror part and the second mirror part are cooled down to a first cooling temperature at a first cooling rate of less than or equal to 100 K/h.

An optical system for a projection exposure apparatus comprises: a first component; a second component which is actuable within an actuation region relative to the first component; and an end stop device which permits a movement of the second component relative to the first component within the actuation region and which blocks it outside the actuation region. The end stop device comprises a bending element having a stiffness which increases abruptly upon reaching a limit of the actuation region to block the movement of the second component relative to the first component.

An extreme ultraviolet light generation system includes a chamber including a first region; a target supply unit supplying a target to the first region; a laser device outputting pulse laser light; an optical system including an optical element to guide the pulse laser light to the first region; an irradiation position adjustment mechanism adjusting a laser irradiation position; an EUV light concentrating mirror arranged such that the pulse laser light passes outside the EUV light concentrating mirror and is guided to the first region; a plurality of EUV sensors measuring radiation energies of the EUV light radiated from the first region in mutually different radiation directions, and having a geometric centroid located at a position away from the optical axis in a direction toward the EUV light concentrating mirror; and a processor controlling the irradiation position adjustment mechanism as setting a target irradiation position of the pulse laser light.

A projection optical unit for EUV projection lithography has a plurality of mirrors for imaging an object field into an image field with illumination light. At least one of the mirrors is an NI mirror and at least one of the mirrors is a GI mirror. A mirror dimension Dx of the at least one NI mirror in a plane of extent (xz) perpendicular to a plane of incidence (yz) satisfies the following relationship:

4 LLWx/IWPV.sub.max<Dx.

A mirror dimension Dy of the at least one GI mirror in the plane of incidence (yz) satisfies the following relationship:

4 LLWy/(IWPV.sub.max cos(a))<Dy.