基于微增减材复合制造的金刚石薄膜图形化技术研究

A novel hybrid additive and subtractive micro-manufacturing method is proposed for patterning of diamond films, which is based on laser ablation and CVD diamond deposition. Laser ablation is firstly employed for patterning process, which is conducted on conventional diamond films. Subsequently, CVD ultra-nano-crystalline diamond deposition is carried out on as-ablated patterned diamond films, and the surface damages of as-ablated patterned diamond films caused by laser ablation, such as graphite, crack on the pattern edge, stress concentration, etc., are reapired. The research contents of this work are as follows. The mapping relationship between the laser fluence, pulse duration and the laser-induced damage of diamond films is studied in depth. The influence of hydrogen etching, homoepitaxial growth, secondary nucleation and growth, annealing, etc. on repairing of film damage and defect during CVD process is investigated systematically. The process of hybrid additive and subtractive micro-manufacturing method is developed, and the patterned diamond films with high quality, high precision and complete micro-structure is prepared. This work is of great importance to enhance the industrialization application of patterned diamond films on MEMS devices.

本项目针对金刚石薄膜图形化加工这一技术问题，提出基于激光刻蚀和CVD金刚石涂层技术的微增减材复合制造新方法。其核心是，以常规金刚石薄膜为加工对象，通过激光刻蚀实施初步图形化加工，随后进行CVD金刚石再沉积，修复激光刻蚀造成的图形化薄膜表面损伤缺陷，包括消除激光刻蚀区内的石墨相，修补图形边缘的崩碎和裂纹，缓解薄膜表面的应力集中等。本项目主要研究内容如下：研究脉冲激光的能量密度、脉冲宽度与金刚石材料表面损伤之间的映射关系；探究氢离子刻蚀、金刚石的同质外延生长和二次形核生长以及退火反应等CVD沉积中的物理化学过程对图形化金刚石薄膜表面损伤的影响规律和修复效果；开发微增减材复合制造工艺，制备高质量、高精度并且微细结构完整的图形化金刚石薄膜。本项目对于推动图形化金刚石薄膜在MEMS领域的应用产业化具有重要意义。

针对金刚石薄膜高质量图形化加工的难题，本研究基于激光刻蚀和CVD再沉积工艺，提出了微增减材复合制造方法，系统研究了激光刻蚀能量密度、脉冲宽度与金刚石薄膜表面损伤的映射关系以及CVD沉积工艺对金刚石表面损伤的影响机理及修复效果，在此基础上进行面向图形化金刚石薄膜的微增减材复合制造工艺优化。本研究基于上述研究内容，开发了激光微细加工金刚石材料的工艺，采用CVD原位反应调控金刚石薄膜表面润湿性和修复激光刻蚀造成的表面损伤，利用微增减材复合工艺制备了具有微纳复合微结构的图形化金刚石薄膜。上述研究成果对于开发高质量图形化金刚石薄膜，推动其在6G通讯、MEMS以及生物植入领域的应用具有重要意义。