Stereophonic projection lithography using parabolic mirrors

Stereophonic lithography applying a magic-mirror optics composed of faced parabolic mirrors is proposed. In the magic mirror system, a real image of an object placed on the base of the lower mirror is formed at the aperture center of upper mirror as if an actual object is floating in the air. The image is formed by illuminating the object by the downward light supplied through the upper mirror aperture. In the new optics originated in this research, a lower mirror with an aperture similar to the upper mirror is used, and the object held at the center of the lower mirror aperture is illuminated obliquely by the upward light supplied through the lower mirror aperture. At first, using reflective objects, image formations were demonstrated. When an object was placed at various height of the optical axis, an image almost similar to the object was projected successfully in a wide height range of the object. The size and the height position of the image were almost regularly changed according to the axial height shift of the object. However, image contrasts sufficiently high for the lithographic patterning were not obtained. For this reason, transparent objects were tried next, and the illumination light was adjusted as most of the light rays hit the middle parts of the upper mirror surface. As a result, considerably high-contrast images were formed. Although some distortions were observed in image shapes, feasibility of the new stereophonic projection system was confirmed. The new technology is prospective.