A projection photolithography method is presented in the paper, which can be used for fabricating continuous surface structure with the aperture of a few micrometers. In the method, a microlens array is used to form minified images of a designed object. When the parameters of the microlens and the object are properly determined, images with minification from hundreds to thousands times can be obtained. Photoresist is used to record the images and patterns with micro or sub-micro critical size could be manufactured. Both geometric and diffraction theory are used for optimizing the parameters and the design process is given. Resist reflow method is used in our experiment for achieving microlens array with the characteristics of a large NA and a small period. The micro-taper array with period 20 μm and aperture of 5 μm was manufactured with the method and the home made microlens array photolithographic system.
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