Ultraviolet Objectives For Submicron Photolithography

This paper will describe the development of two ultra-high resolution, 1/10x reduction lenses corrected for the 365nm. mercury line. Designed for adaptation to current step and repeat cameras, they are suitable for use in the production of SAW filters, microwave circuits, bubble memories and LSI devices requiring sub-micron line geometry. The paper will discuss the problems involved in designing a 0.40 N.A. lens at 365nm. which has both high transmission and diffraction-limited performance over a 4.2mm. field. Special equipment and techniques are also required during the optical and mechanical manufacturing phase in order to produce a lens which will retain the high level of image quality inherent in the design. Testing of these lenses presents another challenge because critical visual inspection is not possible at 365nm. Image quality was verified by measuring the Optical Transfer Function using a very precise knife-edge scanner. Curves showing the measured OTF out to 1400 cycles/mm. will be presented. If available, photographic tests and/or examples of circuitry produced by these lenses will be shown.© (1978) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.