Refractive projection objective for production of semiconductor elements by immersion microlithography, comprises five lens groups and a system screen, forming a single-waist system of light beam diameters

摘要

A refractive projection objective with lens groups LG1-5 of negative, positive, negative, positive and positive refractive power respectively and a system screen between LG4 and LG5, forming a single-waist system with convexities on each side of a point (X) of minimum ray diameter and a ratio of not more than 0.4 between the object-X distance and the object-image distance. A refractive projection objective (RPO) for producing in the image plane an image of a pattern in the object plane, especially with the aid of an immersion medium between the last optical element in the RPO and the image plane. The RPO comprises (starting from the object plane) five lens groups (LG1, LG2, LG3, LG4 and LG5) with negative, positive, negative, positive and positive refractive powers respectively and a system screen (5) which is arranged in a transition zone between LG4 and LG5 so as to form a one-waist system with convexities on the object side (6) and on the image side (8) and a waist (7) between the two convexities with a neck (X) at the narrowest constriction of the light beam. The ratio AT/L = not more than 0.4, where AT is the distance between the object plane and point (X) and L is the distance between object and image. Independent claims are also included for (1) a projection lighting unit for microlithography comprising an RPO as above; (2) a method (M1) for the production of semiconductor elements and other fine-structured components by making a patterned mask, exposing the mask to UV light and projecting an image of the pattern onto a light-sensitive substrate in the image plane, using an RPO as above and passing the light through an immersion medium between the last optical surface and the substrate; (3) a method (M2) for the production of elements as above by placing a light-sensitive substrate in the image plane of the RPO, illuminating the mask with UV light, setting a finite working distance between an output surface for the RPO and an input surface for the substrate (this working distance being adjusted within the illumination time to a value which is smaller than a maximum dimension of an optical near-field of the emergent light) and projecting an image of the pattern on the substrate with the aid of the RPO.