Abstract
This paper reports that the fabrication of the reflowed microlens by the negative tone JSR THB-130 N photoresist can be treated with different thermal treatments using hotplate and oven. The different disk or thin cylinder arrays with diameters of 40–70 μm and thickness of about 7.4 μm were patterned using photolithography technology, and baked at 220°C by two kinds of thermal treatments using hotplate and oven to form reflowed microlens arrays. The spot size of the refractive microlens was then measured by optical microscopy and the total focal length of refractive microlens was simulated by curve fitting the lens profiles. The resolution of the microlens arrays approaches to 400 dpi as coated with Hexamethyldisilizane material. The smallest spot size of about 2.72 μm at the nominal 40 μm microlensis is obtained by the oven heat treatment, and the shortest total focal length of about 150 μm at the nominal 40 μm microlens is achieved by the hotplate heat treatment. The reduced spot size and total focal length of the microlens could improve the density and performance of optical devices and imaging systems.
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Acknowledgements
This work is partially sponsored by National Science Council under contract No NSC 93-2212-E-006-027 and NSC94-2212-E-006-055. We also thank the Center for Micro/Nano Science and Technology (CMNST) in National Cheng Kung University, for the support of process and analysis equipments.
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Chung, C.K., Hong, Y.Z. Fabrication and analysis of the reflowed microlens arrays using JSR THB-130 N photoresist with different heat treatments. Microsyst Technol 13, 523–530 (2007). https://doi.org/10.1007/s00542-006-0193-0
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DOI: https://doi.org/10.1007/s00542-006-0193-0