This study discusses photoresist forming using a composite grayscale to fabricate a Fresnel lens. Grayscale lithography is a common production method used to facilitate the forming of lenses with different curvatures and depths. However, this approach is time consuming and expensive. This study proposes a method for overcoming these obstacles by integrating a digital micromirror device and microscope to supplant the traditional physical grayscale mask. This approach provides a simple and practical maskless optical lithography system. According to the results, the two adjacent grayscales displayed substantial differences between the high grayscale and influence the low grayscale that ultimately affected photoresist formation. Furthermore, we show that change of up to 150% in the slope can be achieved by changing the grayscale gradient in the central zone and the ring profile. The results of the optical experiment show a focus change with different gray gradients.
© 2012 Optical Society of Korea
(040.6040) Detectors : Silicon
(060.0060) Fiber optics and optical communications : Fiber optics and optical communications
(110.3960) Imaging systems : Microlithography
(130.3990) Integrated optics : Micro-optical devices
Original Manuscript: January 18, 2012
Revised Manuscript: May 29, 2012
Manuscript Accepted: May 29, 2012
Published: June 25, 2012
Yi-Hsiang Huang and Jeng-Ywan Jeng, "Forming a Fresnel Zone Lens: Effects of Photoresist on Digital-micromirror-device Maskless Lithography with Grayscale Exposure," J. Opt. Soc. Korea 16, 127-132 (2012)
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