A Maskless Lithography System Based On Digital Micromirror Device (DMD) And Metalens Array

Date of Award


Degree Name

M.S. in Electro-Optics and Photonics


Department of Electro-Optics and Photonics


Imad Agha


Lithography has been the key technology in the information revolution and will almost certainly underpin future technological revolutions based on nanotechnology. Several kinds of maskless lithography methods have been developed in the last few decades. However, these technologies suffer from a variety of difficulties or limitations such as high cost, low throughput, or limited patterns. When considering μm-scaled patterning of highly complicated patterns with higher throughput, the digital micromirror device (DMD) is the most prominent candidate for maskless lithography. On the other hand, flat optics, such as metalenses, provide a promising route to miniaturized, planar, and integrated optical components in maskless lithography systems, combining relatively high efficiency and potentially low cost. Therefore, developing a maskless lithography system based on DMDs and metalens arrays is very attractive for a number of applications, such as integrated circuits, printed circuit boards, microelectromechanical systems, and even semiconductor manufacturing. In this thesis, based on theoretical knowledge and design experience, we have explored the mechanism of the phase modulation of the metalens. According to the relationship between the diameter of dielectric nanopillars and the transmitted light phase, we have designed a focusing metalens with a wavelength of 405 nm. The DMD/metalens-based maskless lithography system has also been implemented. The function of each metalens is to focus the incoming light from assigned micromirrors in the DMD onto the sample. Therefore, an array of focal spots is formed on the photoresist surface for subsequent scanning and exposure. By coordinating and synchronizing the optical beam shutter, the switch of the DMD micromirrors, and the movement of the piezo nano-positioning stage, we can achieve arbitrary patterning in a dot matrix on the photoresist layer with fine pattern resolution.


Optics, Metalens, DMD, Maskless lithography

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