自支撑氮化硅膜结构制备工艺优化

Process Optimization for Fabrication of Self-Supporting Silicon Nitride Film Structure

自支撑氮化硅膜结构一般是基于微纳加工技术来制备的。为了提高膜结构的品质,本文分别对自支撑氮化硅膜结构制备中的干法刻蚀参数和各向异性湿法腐蚀参数进行了研究和优化,其中干法刻蚀参数主要包括反应气体配比和刻蚀时间,各向异性湿法腐蚀参数主要包括腐蚀剂浓度和腐蚀温度。在不同的参数组合下进行实验,使用光学显微镜观察并比较不同样品的表面形貌,得到了较理想的参数组合。在干法刻蚀的反应气体中加入少量O 2可改善刻蚀效果,反应气体配比V(SF 6)∶V(CHF 3)∶V(O 2)=6∶37∶3,刻蚀时间2 min。湿法腐蚀中腐蚀剂在质量分数25%处达到最大的硅腐蚀速率,同时氮化硅表面形貌也较理想。

Generally,the self-supporting silicon nitride film structure is based on micro-nano fabrication technology.Fabrication of self-supporting silicon nitride film structure was studied in this paper,in which parameters of dry etching and anisotropic wet etching were optimized to enhance the quality of self-supporting film structure.Dry etching process included reaction gas ratio and etching time,anisotropic wet etching process involved etchant concentration and etching temperature.First,the experiments were conducted with different parameters.Then the surface morphology of the films fabricated in these experiments were observed by optical microscope,during which the ideal process condition was obtained by comparing the results.It was found that the addition of oxygen to the reaction gas can improve the effect of dry etching,and the best ratio of etching gas is V(SF 6)∶V(CHF 3)∶V(O 2)=6∶37∶3,with 2 min etching time.In wet drying,etching with a mass fraction 25%etchant can achieve the maximum etching rate and ideal surface morphology of silicon nitride film.