Low cost batch fabrication of microdevices using ultraviolet light-emitting diode photolithography technique

Neam Heng Lee; Varghese Swamy; Narayanan Ramakrishnan

doi:10.1117/1.JMM.15.1.010501

25 January 2016 Low cost batch fabrication of microdevices using ultraviolet light-emitting diode photolithography technique

Neam Heng Lee, Varghese Swamy, Narayanan Ramakrishnan

Author Affiliations +

Journal of Micro/Nanolithography, MEMS, and MOEMS, Vol. 15, Issue 1, 010501 (January 2016). https://doi.org/10.1117/1.JMM.15.1.010501

Abstract

Solid-state technology has enabled the use of light-emitting diodes (LEDs) in lithography systems due to their low cost, low power requirement, and higher efficiency relative to the traditional mercury lamp. Uniform irradiance distribution is essential for photolithography to ensure the critical dimension (CD) of the feature fabricated. However, light illuminated from arrays of LEDs can have nonuniform irradiance distribution, which can be a problem when using LED arrays as a source to batch-fabricate multiple devices on a large wafer piece. In this study, the irradiance distribution of an UV LED array was analyzed, and the separation distance between light source and mask optimized to obtain maximum irradiance uniformity without the use of a complex lens. Further, employing a diffuser glass enhanced the fabrication process and the CD loss was minimized to an average of 300 nm. To assess the performance of the proposed technology, batch fabrication of surface acoustic wave devices on lithium niobate substrate was carried out, and all the devices exhibited identical insertion loss of −18 dB at a resonance frequency of 39.33 MHz. The proposed low-cost UV lithography setup can be adapted in academic laboratories for research and teaching on microdevices.

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Neam Heng Lee, Varghese Swamy, and Narayanan Ramakrishnan "Low cost batch fabrication of microdevices using ultraviolet light-emitting diode photolithography technique," Journal of Micro/Nanolithography, MEMS, and MOEMS 15(1), 010501 (25 January 2016). https://doi.org/10.1117/1.JMM.15.1.010501

Published: 25 January 2016

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