深反應離子刻蝕（DRIE）可以對單晶金剛石進行精密加工，制造出獨立的微機械元件。由于其高硬度和剛度以及低機械摩擦，金剛石是納米和微米級元件極具吸引力的材料。然而，由于現有技術的限制（包括淺蝕刻深度和粗糙表面），金剛石的反應離子蝕刻技術一直有一定難度。日前，由瑞士洛桑理工學院的Niels Quack研究組開發出了一種深反應離子蝕刻的工藝，該工藝采用三層Al / SiO2硬掩模，可實現>30μm/ h的蝕刻速率和精確的特征尺寸控制。他們做出的單晶金剛石手表組件厚度為150微米，表面粗糙度在200納米以下。這種新方法為大批量精密制造金剛石部件打下了基礎。

       Deep reactive ion etching of single crystal diamond enables precise fabrication of freestanding micro-mechanical components. Diamond is an attractive material for nano- and microscale components due to its high hardness and stiffness, coupled with low mechanical friction. However, reactive ion etching of diamond is challenging due to several limitations of existing techniques, including shallow etch depths and rough surfaces. 

       Now, a team led by Niels Quack at EPFL in Switzerland report a deep reactive ion etching process that utilizes a three-layer Al/SiO2 hard mask that yields etch rates >30?μm/h and precise dimensional control of features. They demonstrate released single crystal diamond watch components with a thickness of 150?μm and surface roughness better than 200?nm. This new approach paves the way toward high-volume precise fabrication of diamond components.

       Related paper: Precision micro-mechanical components in single crystal diamond by deep reactive ion etching

       Microsystems & Nanoengineering 4, Article number: 12 (2018) 

       doi:10.1038/s41378-018-0014-5