超順磁性光阻懸浮結構之製作與特性量測

本研究係以奈米Fe3O4磁粉及SU-8光阻調配高分子磁性複合材料，開發一簡單新穎之雙層材料曝光製程，製作超順磁性(superparamagnetic)、可光定義圖形(photopatternable)並透過控制曝光量改變厚度之懸浮微結構。暨有磁性物質應用於微機電領域的研究，立體結構圖型定義的方法大多繁瑣複雜，需要多步驟製程才能得到所需之結構。本研究開發雙層材料二次曝光之簡易製程，將懸浮薄膜結構僅在一次顯影步驟內即可完成，省去了多次微影或是其他的蝕刻步驟。研究過程中調整合適之製程參數，直接透過控制曝光量的方法，控制懸浮結構的厚度。可控制的厚度約從20 μm至100 μm，擁有相當大的尺寸範圍。與其他控制懸浮結構厚度的製程方法相較之下，也能有效提升表面的平整度。本研究以此材料及製程成功製作了圓盤薄膜結構，及不同尺寸之雙鉗樑(doubly-clamped beam)結構，並進行位移以及共振頻的特性量測。透過量測磁性複合材料的磁特性曲線，推算施加磁場與結構位移之關係。於長度為6mm之雙鉗樑下施加最大值10.37mT之弦波磁場，能使結構於其共振頻4.18KHz有最大中心位移量224nm。整體而言，結合具有超順磁性、生物相容性、且低成本之奈米鐵氧磁粉、以及同樣具有生物相容性之SU-8光阻作為材料，未來在微流體及生醫領域有許多應用之潛力。

關鍵字

磁性複合材料；超順磁性奈米磁粉；磁性薄膜；微機電系統；雙挾鉗樑

並列摘要

In this work, we propose a novel double-layer photolithography fabrication process which for fabricating microstructures with superparamagnetic photopatternable composites. The traditional method for patterning superparamagnetic composites requires multiple photolithography or etch processes. The proposed method need only a single photolithography process cycle to realize magnetic suspension microstructure. By using different exposure dose of UV light, the suspension thickness can be varied from 20μm to 100μm. Comparing to other fabrication process, our double layer spin-coated process is not only simpler, but also improves the surface flatness of the structure. Microstructures such as circular diaphragm and doubly-clamped beam are designed and fabricated successfully. We also measured the magnetization curve of the composite consisting of superparamagnetic Fe3O4 nanoparticle and SU8-2050 epoxy-based negative photoresist. The relationship between magnetic field and the deflection of the microstructure were measured and discussed. Also, the resonant frequencies of doubly-clamped structure were measured using a vibrometer. Under sinusoidal magnetic field of 10.37mT amplitude, a beam with 6mm in length is able to vibrate at a resonant frequency of 4.18 kHz with 224nm vibration amplitude.

並列關鍵字

Magnetic nanocomposite ； photopatternable magnetic composite ； MEMS ； doubly-clamped beam ； superparamagnetic material

參考文獻

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超順磁性光阻懸浮結構之製作與特性量測

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