濕式蝕刻製程中晶體系統與異向性侵蝕刻速率對其表面形貌的影響

The influence of crystalline structure and anisotropic etching rate on surface morphology by wet chemical etching

有鑑於濕式化學蝕刻已成為在當代半導體製程與微機電系統元件製備的重要製程技術，為了提升對此關鍵技術的了解，本研究以濕式蝕刻反應機制為基礎，建立相場法(phase-field method)之濕式化學蝕刻理論數值模型，模擬濕式蝕刻製程基板表面形貌的形成與演化過程。理論模型中，考量基板晶體系統異向性的特性，分別建立化學蝕刻反應與原子擴散的異向性公式，以具體描述並掌握其蝕刻表面形貌的演化機制。為增進理論模型的應用性，本研究再分別探討不同蝕刻製程參數，如蝕刻速率、蝕刻方向，以及原子擴散方向等，進行多重數值參數的調整。藉由數值模擬方法，定性、定量觀察表面形貌隨著時間受到不同製程參數的化學蝕刻作用之後，不同晶體系統之蝕刻表面形貌特徵與對反應機制的影響。本研究之數值模擬成果有助於推進化學蝕刻的技術，廣泛地運用到新製程參數的設計與開發上，並擴大濕式化學蝕刻技術的實際應用面。

 

Nowadays, the chemical etching technique had become one of the most important processes in the advanced semiconductor manufacturing and microelectromechanical systems. In this study, a theoretical model based on the phase-field method is developed to investigate the formation and evolution of surface morphologies during chemical etching processes. In the formation mechanisms of etched surface morphologies, the anisotropic diffusion of atoms and the anisotropic etching kinetics are both taken into consideration. To enhance the applications of this theoretical model, various etching parameters such as the crystalline structure of substrate and the anisotropic etching rate, corresponding to the different etching conditions are also examined in the numerical calculations. Accompanying with the quantitative analyses of the simulations, the influence of the etching parameters on the formation of surface morphologies during the etching process could be distinctly demonstrated. With the systematic investigations, this study is expected to improve the technique of the chemical etching and the development of the new manufacturing parameters for the applications in the realistic fabrication.