高深宽比硅台阶落差结构的精密成型  

Precision Molding of High Aspect Ratio Silicon Stepped Drop Structure

作　　者：丁景兵 黄斌 何凯旋 赵三院 DING Jing-bing;HUANG Bin;HE Kai-xuan;ZHAO San-yuan(East China Institute of Photo Electron IC,Bengbu 233030,China)

机构地区：[1]华东光电集成器件研究所,安徽蚌埠233030

出　　处：《真空》2022年第2期81-84,共4页Vacuum

摘　　要：针对MEMS深硅台阶刻蚀产生硅草导致器件短路的问题,分析了硅草形成的原因,通过对深硅台阶刻蚀的主要工艺参数,如刻蚀钝化时间、Ar物理轰击设置单因素实验,提出一种基于Bosch工艺,即采用周期性“刻蚀-钝化-预刻蚀”进行精密台阶结构落差成型的方法,该方法主要通过大幅度提高预刻蚀偏置功率和合理配置刻蚀钝化时间来进行实验。结果表明:在预刻蚀偏置功率100W、预刻蚀时间0.8s的工艺条件下,可以有效的抑制硅草的产生;台阶刻蚀完成后再采用SF6刻蚀气体对台阶侧壁清扫10s,确保硅草去除完全,此时获得的台阶落差结构平整光滑,刻蚀的梳齿垂直度优于90°±1°。该方法 具有重复性好、工艺简单的特点。Aimed at the problem of device short circuit caused by MEMS step etching, a method based on Bosch is proposed by analyzing the reason for silicon grass formation and the main process parameters of deep silicon step etching, such as etching passivation and Ar physical bombardment, which adopts periodic etching-passivation-pre-etching to form the precision step structure. The method greatly improves the bias power and time of reasonably allocating etching. The results show that, under the process conditions of pre-etching bias power of 100W and pre-etching time of 0.8s, the production of silicon grass can be effectively suppressed. After step etching is completed, SF6 etching gas is used to clean the step silicon grass for 10s to ensure that the silicon grass is completely removed. At this time,the step drop structure obtained is flat and smooth, and the verticality of the etched comb teeth is better than 90 °±1 °. This method has the characteristics of good repeatability and simple process.

关 键 词：台阶刻蚀 高深宽比 预刻蚀 硅草 BOSCH 

分 类 号：TH703[机械工程—仪器科学与技术] TN305.94[机械工程—精密仪器及机械]