濕式蝕刻釋放以面型微加工共用製程製造之微光學元件的技術探討

Investigation of Wet Etching for Releasing the Micro Optical Devices with MATA Fabricated by Surface Micromachining Common Process

蔡健忠(Chien-Chung Tsai) ； 黃奕澄(Y-Cheng Huang) ； 施湘農(Shannon Shy) ； 林宗煌(Zong-Huang Lin) ； 陳紀佑(Chi-Yu Chen)

《明新學報》 33期 (2007/07) Pp. 337-348

https://doi.org/10.29688/MHJ.200707.0020

摘要

結構的釋放(Release)可說是製造微機電元件後製程中關鍵的步驟，本文利用探微科技股份有限公司(tMt) SMart(上標 ®) (Surface Micromachining for applications and research technology platform) 面型微細加工平台所製造的微光學元件，探討其微結構的釋放。實驗中以濕式蝕刻(Wet Etching)為釋放微結構的主要方法，並利用BOE (7:1)、BOE(6:1)、HF 49%及HF 49%:界面活性劑(10:1)，分別蝕刻SMart(上標 ®)共用製程中的犧牲層－低溫氧化矽材料，觀察釋放微結構的情形。實驗結果顯示微元件利用BOE (7:1)及BOE (6:1)蝕刻液進行微結構的釋放，會對Poly-Si材料產生嚴重侵蝕，造成外觀幾何尺寸與所設計的尺寸有很大的出入，並且耗時。以HF 49%蝕刻液進行微結構釋放時，可在保持外觀幾何尺寸完整下，成功釋放其微結構，但Poly 1 Layer 表面會有殘留的低溫氧化矽，為改善此情形，在蝕刻液中擬加入界面活性劑，藉此改進Poly-Si表面殘留低溫氧化矽的情形。實驗證明利用HF 49%:界面活性劑(10:1)的混合液進行蝕刻，除可成功釋放出微結構外，並可有效改善Poly 1 Layer 表面殘留低溫氧化矽的情況，且與BOE蝕刻液比較，明顯縮短後製程時間。

關鍵字

面型微加工 ； 微陣列式熱致動器 ； 濕蝕刻 ； 犧牲層

並列摘要

Investigation of wet etching for releasing the micro optical devices with Micro Array Thermal Actuator, MATA, fabricated by Surface Micromachining common process is presented in this paper. Releasing the micro structure is the key step during the post process of micro fabrication. Surface Micromachining for applications and research technology, SMart, is a 3P1M common process for serving as the multi project wafer technology platform. SMart is owned by Touch Micro Technology Cooperation in Taiwan. BOE (7:1), BOE (6:1), 49%HF and 49%HF: surfactant (10:1) are adopted as the etchant for releasing the micro optical devices in experiments. Low Temperature Oxide, LTO, is a sacrificial layer material and the etching phenomena will be demonstrated by the four etchants during the releasing process. The experimental results show Poly-Si is seriously damaged and geometrical dimensions of the micro structure are reduced by BOE (7:1) or BOE (6:1) etching compared with the original design. On the other hand, the geometrical features of the micro devices are consistent with the original design and successfully released by 49%HF etching. However, there are a lot of residual LTO on the surface of Poly 1 layer during the 49%HF etching process. Nevertheless, the residual LTO on the surface of Poly 1 layer is significantly reduced by the 49%HF: surfactant (10:1). Finally, the micro optical devices fabricated by SMart common process are successfully released by the 49%HF: surfactant (10:1) and the surface of devices are relatively smooth. Besides, the etching time of the 49%HF: surfactant (10:1) is shorter than that of BOE for releasing the micro optical devices during the post process.

並列關鍵字

surface micromachining ； micro array thermal actuator ； wet etching ； sacrificial layer

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