ILLUMINATION SYSTEM HAVING SPATIALLY SEPARATE VERTICAL AND HORIZONTAL IMAGE PLANES FOR USE IN PHOTOLITHOGRAPHY

摘要

An illumination system having spatially separate horizontal and vertical intermediate image planes. A beam expander is used to expand a laser beam and direct the light to a lens array. A condenser projects and concentrates the light from the lens array into a spatially separate vertical and horizontal intermediate image planes. A relay re-images the spatially separate vertical and horizontal intermediate image planes at a single plane at a reticle. The image of the reticle is thereby projected onto a wafer. Width adjusting means and height adjusting means are located at the respective horizontal and vertical intermediate image planes. The zoomable beam expander is used to change the partial coherence independently in both planes without loss of light. The changeable lens array is used to independently change the two-dimensions of the field of view of the illumination system without loss of light. The physically separate horizontal and vertical intermediate image planes permits facilitating control over the vertical height and horizontal width of the desired rectangular illumination. The rectangular illumination is used to scan a reticle for projection onto a wafer as required in scanning type photolithography in the manufacture of circuits.