隨著奈米科技的興起發展，矽材的應用較廣泛，而石英基材卻相對少有奈米結構的研究及應用。本研究主要藉由鉻(chromium, Cr)金屬薄膜做為蝕刻遮罩(Etch mask)覆蓋於Z-cut石英晶片上，利用濕式蝕刻(wet etching)方式，於不同蝕刻時間將石英晶片上蝕刻出奈米針狀結構(nanoneedle)。研究針對其針狀長度及外形進行分析以了解其機制，並於不同切向之晶片進行相同實驗，觀察其變化和差異。 研究中主要以蒸鍍(evaporation)方式沉積1 nm、2 nm及3 nm鉻薄膜蝕刻遮罩。鉻薄膜在石英晶片上，其原子堆積方式會以島狀成長(island growth)的方式形成，此時利用薄膜還未形成連續膜(continuous film)時，於島狀與島狀間的縫隙，在溫度40 ℃時以飽和濃度之二氟化氫銨(ammonium bifluoride)溶液為蝕刻液(etchant)對石英晶片進行蝕刻，其中以薄膜做為蝕刻遮罩及蝕刻液具有非等向性(anisotropic)的特性，在不同遮罩厚度和蝕刻時間下，使其形成針狀結構，並利用掃描式電子顯微鏡(scanning electron microscope, SEM)觀察針狀結構x方向和y方向之外形及其角度。 研究結果得知，藉濕蝕刻方式及不同厚度之蝕刻遮罩可成功蝕刻出奈米針狀結構，並由掃描式電子顯微鏡可觀察到由於不同遮罩厚度而使得針狀結構形成的速度、長度及輪廓外形都有所差異；也可得知以不同切向之石英晶片蝕刻亦會得到針狀結構，但會因不同切向外形輪廓而有所改變。 This paper presents a study of the fabrication of quartz nanoneedles by wet etching. Using Chromium thin films as etching masks, the quartz nanoneedles are fabricated on Z-cut wafers with different etching time. The lengths and shapes of nanoneedles are observed using scanning electron microscope (SEM) to study the anisotropy of the quartz etching and the mechanism of the needle formation. Nanoneedles fabricated on other orientation quartz wafer are also demonstrated. In the present study, 1 nm, 2 nm and 3 nm Cr thin films are deposited on quartz wafers as etching masks by evaporation. Accumulation of atoms form metal layers from individual Cr islands to continuous films. Ammonium bifluoride is used as the etchant to etch quartz chip at 40℃. With quartz anisotropic etching, nanoneedles are formed with different mask thickness and etching time. In conclusion, we have successfully fabricated the quartz nanoneedles by wet etching. From the study, we observe the relationship between anisotropic etching and the shapes of the nanoneedles. This study may help for future development in quartz MEMS.
