Light source filter for projecting masking images on to semiconductor wafers for lithographic micro-miniaturisation process

摘要

A means fo projecting a high resolution mask image onto a semiconductor wafer (10) consists of an interference filter (3) that has multiple reflection surfaces contains a semi transparent film (3) as a substrate on a transparent region (33) a light source (1) emits light passed through a lens (2) to provide light (61) with high coherence. The filter output (62) is one half the wavelength of the input and is passed through a condenser lens (4) to the mask (5) containing the image pattern. The diffracted light beams (71, 72) have a half wavelength phase difference and are passed through the projection lens (8) and are focussed on the wafer.