| 摘要 |
A small field scanning photolithography system (700) has a double pass Wynne-Dyson optical system (770) which provides an erect, non-reverted, unmagnified image. An optical path through the system passes from an object (722), reflects off an input reflector (731), passes through a first quadrant of a lens (740), reflects off a concave mirror (750), passes through a second quadrant of lens (740) into folding optics (732) where an intermediate image forms, passes from folding optics (732) through a third quadrant of lens (740), reflects off concave mirror (750) a second time, passes through a fourth quadrant of lens (740), and finally reflects off an output reflector (733) to a plane (160) where a final image (362) forms. Typically, input and output reflectors (731, 733) and the folding optics (732) are prisms. A field stop (760) may be provided in folding optics (732) where the intermediate image forms. Magnification adjusting optics (710, 720) can be added to input and output prisms (731, 733) or to folding optics (732). The magnification adjusting optics (710, 720) forms two narrow meniscus air gaps (713, 723) which are equal size for unity magnification. Narrowing one air gap (713 or 723) and widening the other air gap (723 or 713) changes magnification slightly. |
