US 6,353,470 B1 · Microlithography reduction objective and projection exposure apparatus

Abstract

The invention concerns a microlithography projection objective device for short wavelengths, preferably <100 nm with a first (S1), a second mirror (S2), a third (S3), a fourth mirror (S4), a fifth (S5) and a sixth mirror (S6). The invention is characterized by the fact that the image-side numerical aperture is NA≧0.15 and that the mirror nearest to the object to be illuminated, preferably nearest to the wafer, is arranged in such a way that the image-side optical free working distance corresponds at least to the used diameter D of this mirror nearest to the wafer and/or the image-side optical free working distance is at least the sum of a third of the used diameter D of this mirror and a length which lies between 20 mm and 30 mm, and/or the image-side optical free working distance is at least 50 mm, preferably 60 mm.

Claims39

Dependent claims

A projection objective for use in short wavelength microlithography, comprising;

six mirrors (a first mirror (S1), a second mirror (S2), a third mirror (S3), a fourth mirror (S4), a fifth mirror (S5) disposed closest to an object to be illuminated and a sixth mirror (S6)) arranged such that an image-side numerical aperture (NA) is NA≧0.15, and wherein said fifth mirror is positioned such that at least one of the following conditions is satisfied:
an image-side optical free working distance is greater than or equal to a used diameter D of the fifth mirror;
the image-side optical free working distance is greater than or equal to a sum of one-third of the used diameter of the fifth mirror and a length between 20 mm and 30 mm;
and
the image-side optical free working distance is at least 50 mm.

2 more elements

Dependencies are inferred from the claim text.

Microlithography reduction objective and projection exposure apparatus

Life of this patent

Microlithography reduction objective and projection exposure apparatus

Life of this patent

Abstract

Claims39