摘要 由於石英材料具有壓電性質以及高的頻率穩定性等良好的特性，因此近年來石英材料於MEMS及微感測器上的應用很廣泛，例如：生醫方面，可做為液態有機物的分析檢測器；而在微感測器方面，則有石英晶體微天平，可於工業安全與環保上用以檢測氣體；而在石英元件上則有石英震盪器、表面聲波濾波器及石英音叉元件等應用。而石英的蝕刻製程，以乾蝕刻相對於濕蝕刻來說，乾蝕刻的製程成本要比濕蝕刻貴上許多，因此本論文則以濕蝕刻的方式來探討濕蝕刻之微柱狀結構及微針狀結構，而微柱狀及微針狀結構在石英表面上具有表面改質以及增加表面特性之用。 本研究主要以濕蝕刻製程來探討石英微結構之X方向與Y方向之蝕刻率，且針對其結構外形與遮罩圖形進行分析，整理出石英蝕刻之相關方程式，用以預測開口寬度等各項參數，並探討高密度針狀結構之間的關係，與其限制。 研究中主要以電子束蒸鍍的方式沉積鉻金屬薄膜與金金屬薄膜於石英試片上，做為蝕刻遮罩，並利用微影製程將光罩上之圖形轉移至試片上作為蝕刻圖形，之後將金薄膜與鉻薄膜蝕刻去除，於不同遮罩下以蝕刻溫度為55℃，濃度為飽和濃度之二氟化氫銨為蝕刻液進行蝕刻，利用金屬薄膜作為蝕刻遮罩及非等向性蝕刻的特性，在不同遮罩圖形及蝕刻時間下，使石英試片形成微結構，並利用SEM觀察其結構之X方向、Y方向以及石英蝕刻後基座之外形與角度，並利用SEM圖對石英蝕刻結構進行量測。 研究結果可得，不同遮罩圖形之X方向與Y方向各結構平面的蝕刻率，且由側向蝕刻與縱向蝕刻建立蝕刻關係式，並利用所建立的蝕刻關係式，導出針對濕蝕刻製程之針狀微結構的預測方法，再利用不同遮罩寬度下之預測值與實驗值作驗證，可知預測值與實驗值雖有誤差，但大致上蝕刻率的趨勢是一致的。而整理出各平面的蝕刻率、蝕刻角度以及蝕刻關係式等資訊，更可以運用於預測蝕刻後石英元件的尺寸，對石英元件之製造及研發有相當大助益。 Abstract Quartz has many remarkable characteristics such as piezoelectricity nature, high frequency, and thermal stability. It has been widely used as the main materials for oscillators, resonators, and surface acoustic wave filters. In recent years, quartz has been used in micro-sensors and MEMS applications, such as quartz SAW micro-sensors for biological analysis, and quartz microbalance for gas detection. To make quartz micro-sensors, it usually requires etching processes. Comparing dry and wet etching techniques of quartz, the cost of dry etching has more preferable profile control but is much more expensive than the wet etching. It is very attractive to make complex structures using wet etching. In this thesis, we develop wet etching technique to fabricate micro-pillars and micro-needles which have potential usages in increasing sensitivity of micro-sensors and surface modification. To fabricate the structures, chromium and gold thin film is evaporated on the quartz substrate and patterned as etching masks. The sample is then etched in ammonium fluoride solution of saturated concentration at 55℃. Due to the anisotropic etching property, micro-pillars can be formed. The etched profiles are observed using SEM to establish etching rate in the X direction, Y direction, and the shape and angle of the base structure. Using the experimental data, the etching criteria and equations can be established that provide ways for the predictions of the grows of high-density micro-pillars. The experimental etching profiles of micro-pillars consist with the prediction. This research is helpful for developing novel MEMS devices.
