Patent Number: 7,085,075

Title: Projection objectives including a plurality of mirrors with lenses ahead of mirror M3

Abstract: According to one exemplary embodiment, a projection objective is provided and includes at least two non-planar (curved) mirrors, wherein an axial distance between a next to last non-planar mirror and a last non-planar mirror, as defined along a light path, is greater than an axial distance between the last non-planar mirror and a first refracting surface of lenses following in the light path. In one exemplary embodiment, the first refracting surface is associated with a single pass type lens. The present objectives form images with numerical apertures of at least about 0.80 or higher, e.g., 0.95. Preferably, the objective does not include folding mirrors and there is no intermediate image between the two mirrors, as well as the pupil of the objective being free of obscuration.

Inventors: Mann; Hans-Juergen (Oberkochen, DE), Hudyma; Russell (San Ramon, CA), Epple; Alexander (Aalen, DE)

Assignee: Carl Zeiss SMT AG

International Classification: G02B 17/00 (20060101)

Expiration Date: 8/01/02018