Maskless lithography based on digital micromirror device (DMD) and double sided microlens and spatial filter array

摘要

A new type of maskless lithography system based on digital mirror device (DMD) is proposed, constructed, and experimentally demonstrated. It includes a pin-hole array sandwiched by two microlens arrays on each side, known as double-sided microlens/spatial-filter array (D-MSFA), and aligned with a DMD. Ultraviolet (UV) light reflected by DMD is first collected by the first microlens array, filtered through the pin-hole array, and then refocused by the second microlens array into a UV spot array. Along with an obliquely scanning method, this D-MSFA/DMD-based maskless lithography system can perform not only 2D but also 3D UV patterning. Experimental testing successfully generates complicated patterns with a minimum line-width of 3.36 mu m. Direct 3D patterning and 3D microfabrication are also experimentally demonstrated on a photoresist layer. Excellent profile accuracy and surface structure qualities are observed with great potentials for future 2D and 3D microfabrication in a maskless manner.