2011YHL

林郁欣 (Yu-Hsin Lin)

Development of Polymer Passivation Layer for Suspended Silicon Structures Etching Fabrication Platform

高分子蝕刻保護層於單晶矽懸浮結構之製程平台開發

In recent year, MEMS products have been widely used in various industries, especially in the 3C manufactures. The rapid and stable fabrication platform technology of the process plays a very important role in industrial development. This paper presents a rapid bulk micromachining process named Polymer Passivation Layer for Suspended structures Etching (PoPLSE) by using polymer as protecting passivation layer at both anisotropic and isotropic etching steps. The proposed method can fabricate suspended single-crystal-silicon (SCS) structures in Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE) chamber directly, which would simplify the fabrication process and save fabrication time.

In anisotropic silicon etching, the basic parameters have been systematical studied in the paper. For the different etching specifications, such as verticality, aspect-ratio, roughness, lateral etching and etching rate, etc., the optimum recipe of high-aspect-ratio etching process, smooth etching process and nano-scale etching process parameters have been developed for different applications.

The current study systematically investigates critical fabrication parameters to verify feasibility of the proposed PoPLSE fabrication platform method, and discusses the polymer passivation time and removal time of polymer at the base of substrate at different opening gaps of 5, 10, 30, and 50 μm and different depths of 30 and 50 μm to establish suitable recipes for fabricating suspended structures. The suitable recipes for comb-drive microstructures with 30μm or 60μm in depth and 5μm or 10μm line width at different opening sizes are experimentally identified. It is also shown that the proposed method can fabricate not only the suspended microstructures with the same thickness, but also suspended microstructures with different thickness, as well as in sub-micro scale. Finally, an innovative compensative structure assisted ICP-RIE etching to fabricate SCS blaze-type micro-grating have been proposed. The micro-grating have successfully fabricated using anisotropic etch and suspended structure technology.

[1] H.-L. Hsu, Y.-R. Chang, Y.-H. Lin, and W. Hsu (June 2006). A novel self-aligned process between the nano-aperture and solid immersion lens, The 3rd Asia-Pacific Conference of Transducers and Micro-Nano Technology, Singapore.

[2] Y.-H. Lin and W. Hsu (July 2010). Feasibility Study on Using Polymer as Protecting Material in Fabricating Suspended Single-Crystal-Silicon Microstructures,5th Asia-Pacific Conference on Transducers and Micro-Nano Technology, Perth, West Australia.

[3] Y.-H. Lin, C. J. Weng, C. Y. Su, and W. Hsu (March 2012). Fabrication of Deep Lateral Single-Crystal-Silicon Blaze Micro-grating by Inductively-Coupled-Plasma Reactive Ion Etch, The 7th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Kyoto, Japan.

[4] Y.-C. Shieh, R.-P. Ma, W. Hsu, Y.-H. Lin, and Y.-H. Tang (October 2012). A Reversible Micro Mechanical-latch Shock Switch by External Magnetic Field. The 11th IEEE Conference on Sensors, Taipei, Taiwan.

[5] Y.-H. Lin and W. Hsu, “Polymer as the protecting passivation layer in fabricating suspended SCS structures at both anisotropic and isotropic etching.” Journal of Micromechanics and Microengineering 2012, 22, 045015.

[6] Y.-B. Wang, Y.-H. Lin, and W. Hsu (April 2014). Spin coating of uniform photoresist for pattern transfer on micromachined 3-D surfaces. The 9th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Hawaii, U.S.A..