低成本厚膜光阻製程於微機構驅動式光學開關之研製

Abstract

負型SU-8 厚膜光阻利用一般的微影製程，即可製作高深寬比的微結構。目前SU-8光阻主要是應用於LIGA 電鑄製程之模板、熱壓成形之模仁、微光合成形、光波導、微流體應用流道或微機械結構等之材料，然而尚未有直接將SU-8 光阻作為微致動器材料的研究。本計畫目的即是利用SU-8 厚膜光阻微影製程，低成本且快速地開發微光學應用之微反射鏡式光開關元件。全SU-8 厚膜光阻的製程與微結構，其優點為低成本、可降低微反射鏡因組裝所造成的誤差，利用間接驅動方式增加微反射鏡的作動行程，以增進光路切換的適用範圍。製作完成之微反射鏡式光開關，採用靜電式致動器，經局部結構釋放且鍍金屬膜後，成功地以AC 125 伏特電壓驅動；微反射鏡對光波長632 nm 之可光源與光波長1550 nm 之紅外光源皆有反射效能， 其反射效率分別為17.6% 及20.5% 。

The research will develop the electrostatic micromechanism-drive optical switch through the combination of low-cost SU-8 thick resist process and etch release technique. The SU-8 resist will be used as the body material of micromechanism and micromirror of optical switch; this will directly avoid the stripped difficulty and inconvenient assembly like MUMPs process. Besides, the microactuator fabricated by SU-8 will make the driving response larger than the one fabricated by metal. This will be more suitable for the application of micro-opto-electro-mechanical system (MOEMS). We have finished optical switch, which was all in one not assembled. Advantages of optical switch are low cost, decrease microstructures assembled tolerances and increase active range of micromirror by being driven indirectly. In our study, Actuators of optical switch, which was sputtered metal, are driven by AC 125V. Reflective ratio of micromirror is 17.6% in visible wavelength (632nm) and 20.5% in IR wavelength (1550nm).