Patent ID: 7312847
Filing Date: 2007-12-25
Classification: G02B,G03F

Abstract:
1. A projection objective for projecting a pattern arranged in an object plane of the projection objective into an image plane of the projection objective comprising: a plurality of lenses including a first lens group and a second lens group; a plurality of lenses forming an image-side belly of the projection objective arranged between a negative third lens group with negative refracting power upstream of the image-side belly and the image plane, the image-side belly including a last optical element closest to the image plane; an aperture stop positioned within the image-side belly; the lenses forming the image-side belly including a positive fourth lens group with positive refracting power immediately upstream of the aperture stop between the negative third lens group and the aperture stop and a positive fifth lens group with positive refracting power immediately downstream of the aperture stop between the aperture stop and the image plane; the projection objective being an immersion objective adapted to project the pattern arranged in the object plane into the image plane with the aid of an immersion medium arranged between the last optical element of the projection objective and the image plane.