An optical projection unit includes first and second optical element modules. The first optical element module includes a first housing unit and a first optical element received within the first housing unit and having an optically used first region defining a first optical axis. The second optical element module is located adjacent to the first optical element module and includes a second optical element which defines a second optical axis of the optical projection unit. The first housing unit has a central first housing axis and an outer wall extending in a circumferential direction about the first housing axis. The first optical axis is laterally offset and/or inclined with respect to the first housing axis. The first housing axis is substantially collinear with the second optical axis.

A projection objective configured to image an object field in an object plane into an image field in an image field plane includes a reflective unit, a first refractive unit, and a second refractive unit. An optical axis of the first refractive unit is parallel to but displaced from an optical axis of the second refractive unit. The reflective unit includes a first curved mirror and a second curved mirror. The second curved mirror is immediately downstream from the first curved mirror in a path of light from the object plane to the image plane. The projection objective is a microlithography projection objective.

A catadioptric projection objective has a first objective part, defining a first part of the optical axis and imaging an object field to form a first real intermediate image. It also has a second, catadioptric objective part forming a second real intermediate image using the radiation from the first objective part. The second objective part has a concave mirror and defines a second part of the optical axis. A third objective part images the second real intermediate image into the image plane and defines a third part of the optical axis. Folding mirrors deflect the radiation from the object plane towards the concave mirror; and deflect the radiation from the concave mirror towards the image plane. The first part of the optical axis defined by the first objective part is laterally offset from and aligned parallel with the third part of the optical axis.

A projection exposure apparatus includes a catadioptric projection objective, an illumination system, a stage, and a control unit. The catadioptric projection objective includes multiple objective parts, and one or more active manipulators coupled to one or more optical elements of the projection objective. The control unit is programmed to cause the one or more active manipulators to act on one or more corresponding optical elements while the stage scans a wafer with respect to an image field to reduce errors in the image at the image field.

Projection optical system for forming an image on a substrate and including an illumination relay lens and a projection lens each of which is a catadioptric system. The projection lens may include two portions in optical communication with one another, the first of which is dioptric and the second of which is catadioptric. In a specific case, the projection optical system satisfies

[00001]$4<\frac{.Math.{}_I.Math.}{.Math.{}_T.Math.}<30,$

where .sub.I and .sub.T are magnifications of the first portion and the overall projection lens. Optionally, the projection lens may be structured to additionally satisfy

[00002]$6<\frac{.Math.{}_{\mathrm{II}}.Math.}{.Math.{}_T.Math.}<20,$

where .sub.II is a magnification of the second portion. A digital scanner including such projection optical system and operating with UV light having a spectral bandwidth on the order of 1 picometer. Method for forming an image with such projection optical system.

An optical projection unit includes first and second optical element modules. The first optical element module includes a first housing unit and a first optical element received within the first housing unit and having an optically used first region defining a first optical axis. The second optical element module is located adjacent to the first optical element module and includes a second optical element which defines a second optical axis of the optical projection unit. The first housing unit has a central first housing axis and an outer wall extending in a circumferential direction about the first housing axis. The first optical axis is laterally offset and/or inclined with respect to the first housing axis. The first housing axis is substantially collinear with the second optical axis.

Projection optical system for forming an image on a substrate and including an illumination relay lens and a projection lens each of which is a catadioptric system. The projection lens may include two portions in optical communication with one another, the first of which is dioptric and the second of which is catadioptric. In a specific case, the projection optical system satisfies $4<\frac{.Math.{}_I.Math.}{.Math.{}_T.Math.}<30,$
where .sub.I and .sub.T are magnifications of the first portion and the overall projection lens. Optionally, the projection lens may be structured to additionally satisfy $6<\frac{.Math.{}_{\mathrm{II}}.Math.}{.Math.{}_T.Math.}<20,$
where .sub.II is a magnification of the second portion. A digital scanner including such projection optical system and operating with UV light having a spectral bandwidth on the order of 1 picometer. Method for forming an image with such projection optical system.

A stop, such as a numerical aperture stop, obscuration stop or false-light stop, for a lithography apparatus, includes a light-transmissive aperture and a stop element, in which or at which the aperture is provided. The stop element is opaque and fluid-permeable outside the aperture.

Described are optical systems for a digital micromirror device (DMD) illuminator. The optical systems include a LED array, a tapered non-imaging collection optic, a reflective stop and a telecentric lens system. The telecentric lens system is disposed along an optical axis defined between the tapered non-imaging collection optic and the reflective stop. The telecentric lens system is configured as a first half of a symmetric one to one imager for an object plane on the optical axis and as a second half of the symmetric one to one imager for optical energy reflected from the reflective aperture stop. The optical systems reclaim optical energy emitted by the LED array that does not initially pass through the reflective stop and provide an improved intensity distribution at the DMD. Reductions in stray light and the thermal loads on the illuminator and DMD are achieved relative to conventional illumination systems for DMDs.

Projection optical system for forming an image on a substrate and including an illumination relay lens and a projection lens each of which is a catadioptric system. The projection lens may include two portions in optical communication with one another, the first of which is dioptric and the second of which is catadioptric. In a specific case, the projection optical system satisfies $4<\frac{.Math.{}_I.Math.}{.Math.{}_T.Math.}<30,$
where .sub.I and .sub.T are magnifications of the first portion and the overall projection lens. Optionally, the projection lens may be structured to additionally satisfy $6<\frac{.Math.{}_{\mathrm{II}}.Math.}{.Math.{}_T.Math.}<20,$
where .sub.II is a magnification of the second portion. A digital scanner including such projection optical system and operating with UV light having a spectral bandwidth on the order of 1 picometer. Method for forming an image with such projection optical system.