Patent ID: 7187503

Claim:
A refractive 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 first lens group with negative refractive power following the object plane; a second lens group with positive refractive power following the first lens group; a third lens group with negative refractive power following the second lens group; a fourth lens group with positive refractive power following the third lens group; a fifth lens group with positive refractive power following the fourth lens group; and a system aperture that is arranged in a transition region from the fourth lens group to the fifth lens group, so as to form a single-waist system with an object-side belly, an image-side belly and a waist, arranged between the object-side belly and the image-side belly, with a constriction site of narrowest constriction of a beam; wherein: the projection objective is designed as an immersion objective for projecting a pattern arranged in an object plane of the projection objective into an image plane of the projection objective with the aid of an immersion medium arranged between a last optical element of the projection objective and the image plane; a waist distance AT exists between the object plane and the constriction site, and the condition AT/L≦0.4 holds for a distance ratio AT/L between the waist distance AT and an object-image distance L of the projection objective; and the object-side belly has a first diameter D 1 , the image-side belly has a second diameter D 3 , and a belly diameter ratio D 3 /D 1 >1.5.