| 摘要: | 近年來物聯網(Internet of Things, IoT)與5G無線通訊的興起更帶動了高頻與小型化石英振盪器的需求，傳統以機械式切割及研磨加工的製程方式已無法符合逐步小型化的石英晶體材料型貌控制需求，使其石英振盪器能量閉鎖效應不佳，導致頻率穩定性也受到影響，為了滿足石英振盪器電性規格日益嚴苛的需求，石英振盪晶片製作技術將面臨轉型。
本研究將探討AT-CUT石英振盪元件的石英外型微結構雙面蝕刻製程研究，在考量石英非等向性材料複雜的特性下，規劃先進行石英蝕刻機理研究，其目的是為了觀察影響石英蝕刻速率及石英表面型貌的關鍵因子，並確認穩定蝕刻的製程條件。
完成石英蝕刻機理研究後，以最佳的製程條件，再透過不同的光罩尺寸設計，以黃光微影製程結合濕式蝕刻製程，對石英X軸向與Z軸向進行單面石英蝕刻後，再對剖面輪廓觀察與分析，並依據單面石英蝕刻後的結構特徵的定義，來觀察及分析不同軸向於單面石英的蝕刻後的各結構特徵對應光罩尺寸的關係，接續再針對X軸向與Z軸向進行雙面石英蝕刻後的剖面輪廓觀察與分析，此階段研究重點為X軸向與Z軸向蝕刻後的邊界結構特徵，並與單面蝕刻研究觀察的結果進行比對分析，可觀察到雙面石英蝕刻後於Z軸向的邊界結構特徵是不穩定的，且呈現反對稱的現象，X軸向的邊界結構特徵則是穩定的。
由雙面石英蝕刻後的研究結果，再對Z軸向展開實驗規劃，以雙面石英蝕刻未貫穿及光罩錯位的方法，逐步分析與探討影響Z軸向外型結構特徵的成因及控制結構的方法，使石英振盪晶片的振盪特性不會受到外型結構不穩定的影響，並讓石英振盪石器的電性特性獲得穩定的輸出。
關鍵字：石英、AT-CUT、濕式蝕刻、石英非等向性材料
;In recent years, the rise of the internet of things(IoT) and 5G wireless communication has driven the demand for high-frequency and miniaturized resonator. The traditional mechanical cutting and lapping process has been unable to meet the needs of the gradually miniaturized resonator material. The resonator energy trapping effect is also poor, resulting in frequency stability is also affected, in order to meet the increasingly stringent requirements of the resonator electrical specifications, the wafer fabrication technology will face a transformation.
In this study, we will discuss the double-sided etching process of quartz microstructure of AT-CUT quartz oscillator. Under the consideration of the complex characteristics of quartz anisotropic materials, we plan to study the mechanism of quartz etching first, in order to observe the influence of the etching rate of quartz and the key factors of the quartz surface morphology, and confirm the process conditions for stable etching.
After completing the study of the quartz etching mechanism, the optimal conditions are used to design through different mask sizes. The photolithography process is combined with the wet etching process, and the single-sided quartz etching is performed on the X-axis and the Z-axis of the quartz, and then the profile of the section is observed and analyzed. According to the definition of the structural features after single-sided quartz etching, the relationship between the etched structural features of different axial directions on single-sided quartz and the size of the reticle is observed and analyzed, and then the X-axis and the Z-axis are doubled observation and analysis of the profile of the quartz after etching. At this stage, the research focuses on the edge structure characteristics after X-axis and Z-axis etching, and compares the results with the single-sided etching research. The edge structure characteristics of the Z-axis after sided etching can be observed. It is unstable and present antisymmetry, and the edge structure of the X axis is stable.
Based on the research results after double-sided quartz etching, the Z-axis development experiment plan is mask shift with the double-sided quartz etching is not penetrated, and the causes and control structures affecting the Z-axis external structural features are analyzed and discussed step by step. The method makes the vibration characteristics of the resonator wafer not affected by the instability of the external structure, and the electrical characteristics of the resonator obtain a stable output.
Keywords：quartz、AT-CUT、wet etching、quartz anisotropic materials |
