New projection exposure using a double-line matrix of optical fibers in place of a reticle

A new projection exposure method devoid of reticles is proposed, and the feasibility of arbitrary pattern printing is confirmed. Preparation of expensive reticles is not favorable for producing small amounts of electric and optical devices or micromachine components, and a long turn around time becomes a fatal bottle neck for adopting various design changes quickly. In the new method, patterns are delineated by superimposing the light spots from an optical fiber matrix. Since the exposed spots are overlapped using a double-line matrix, patterns are stitched smoothly even in the fiber array direction, irrespective of how the fibers with a circular cross section are arrayed. It is clarified that printed patterns become smooth if circular spot exposures are stitched with a pitch smaller than a half pitch of the fiber matrix array. Ejected light intensity from each fiber can be controlled uniformly by polishing all fiber ends simultaneously using emery papers and lapping films, and compensating for residual intensity deviation by inserting color filters. Thus, printing of not only basic line-and-space patterns but also complicated patterns including oblique ones is demonstrated in order to exhibit the feasibility of the proposed method.