Erhard Glatzel

New Lenses For Microlithography

Giving the imaging bundle of rays two substantial bulges makes it possible to design 10x reduction lenses with large aperture and field size for microlithography without using high index glasses with poor transmission.

Reduction lens and illumination system for deep-UV aligners

The optical equipment for DUV-Aligners consisting of an all-quartz lens and an illumination system for a 248 nm narrowband excimer laser has been developed. First the concept of the illumination system is discussed. It was possible to achieve good illumination homogeneity in reticle and pupil planes combined with a reasonable efficiency. Data on illumination intensity and homogeneity is reported. An all-quartz lens which cannot be chromatically corrected has been designed and tested. The 5 : 1 reduction lens has a NA of 0. 42 and can print 0. 5 iim lines and spaces over a field diameter of 21. 2 mm. To obtain diffraction limited resolution a spectral bandwidth of 3 pm is required. Experimental data on optical performance is presented. Changes in environmental conditions can be compensated and do not influence the imaging quality. 1.