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Journal of Micro/Nanolithography, MEMS, and MOEMS

High-resolution maskless lithography
Author(s): Kin Foong Chan; Zhiqiang Feng; Ren Yang; Akihito Ishikawa; WenHui Mei
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Paper Abstract

An innovative high-resolution maskless lithography system is designed employing a combination of low- and high-numerical-aperture (NA) projection lens systems along with integrated micro-optics, and using Texas Instruments' super video graphic array (SVGA) digital micromirror device (DMD) as the spatial and temporal light modulator. A mercury arc lamp filtered for the G-line (λ = 435.8 nm) is used as the light source. Exposure experiments are performed using data extraction and transfer software, and synchronous stage control algorithms derived from a point array scrolling technique. Each exposure scan produces a field width (W) of approximately 8.47 mm with a field length (longitudinal field) limited only by onboard memory capacity. DMD frame rates of up to 5 kHz (kframes/s), synchronized to the stage motion, are achievable. In this experiment, TSMR-8970XB10 photoresist (PR), diluted to 3.8 cP with PR thinner is prepared. The PR is spin-coated onto a chrome-coated glass substrate to 1.0-μm thickness with 0.1-μm uniformity. A 0.4-μm scan step is used and 27,000 DMD data frames are extracted and transferred to the DMD driver. Results indicate consistent 1.8-μm line space (L/S) resolved across the entire field width of 8.47 mm. Given optimized exposure and development conditions, 1.5-μm L/S is also observed at certain locations. The potential of this maskless lithography system is substantial; its performance is sufficient for applications in microelectromechanical systems (MEMS), photomasking, high-resolution LCD, high-density printed circuit boards (PCBs), etc. Higher productivity is predicted by a custom H-line (λ = 405 nm) lens system designed and used in conjunction with a violet diode laser systems and the development of a real-time driver.

Paper Details

Date Published: 1 October 2003
PDF: 9 pages
J. Micro/Nanolith. 2(4) doi: 10.1117/1.1611182
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 2, Issue 4
Show Author Affiliations
Kin Foong Chan, Ball Semiconductor, Inc. (United States)
Zhiqiang Feng, Ball Semiconductor, Inc. (United States)
Ren Yang, Ball Semiconductor, Inc. (United States)
Akihito Ishikawa, Ball Semiconductor, Inc. (United States)
WenHui Mei, Ball Semiconductor, Inc. (United States)

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