Maskless Lithography Based on Digital Micro-Mirror Device (DMD) with Double Sided Microlens and Spatial Filter Array
DEStech Transactions on Engineering and Technology Research
A ultra-violet (UV) maskless lithography system is developed for arbitrary UV patterning. The system consists of an UV illumination system, a digital micro-mirror device (DMD), a projection system, and a double-sided microlens and spatial filter array (D-MSFA). The DMD acts as a virtual mask for generating arbitrary patterns by individually turning on or off of each micro-mirror. The projection lens projects the image of DMD onto the D-MSFA, which consists subsquently the fisrt microlens array
... rt microlens array (MLA 1 ), the pinholes array, and the second microlens array (MLA 2 ). The MLA 1 focus the light from DMD to its corresponding pinhole, and the MLA 2 projects the image of pinhole array onto a substrate to form a point array of UV light. The profiles of microlenses are designed optimized to chieve smallest focused spot size. A method has been developed to fabricate the D-MSFA and to ensure high microlens profile accuracy and excellent alignment between microlens arrays and pinhole array. The obatined UV spot sizze is 10 µm measured at FHMW level, and the system can generate arbitrary patterns with a minimum linewidth of 5.2 µm.