高深宽比深隔离槽的刻蚀技术研究

体硅集成MEMS器件中的一个非常重要的技术就是微结构与电路部分的电隔离和互连。由于体硅工艺与传统CMOS工艺不兼容 ,所以形成高深宽比的深隔离槽 (宽约 3μm ,深 2 0～ 10 0μm)是体硅集成中急待解决的工艺难题。本文采用MEMS微加工的DRIE (DeepReactiveIonEtching)技术、热氧化技术和多晶硅填充技术 ,形成了高深宽比的深电隔离槽 (宽 3.6 μm ,深 85μm)。还提出了一种改变深槽形状的方法 ,使深槽的开口变大 ,以利于多晶硅的填充 ,避免了空洞的产生

Fabrication technique of deep electrical isolation trenches using DRIE and medium refill

Isolation and interconnection between MEMS unit and IC unit are very important for the bulk silicon MEMS devices. However, the process of bulk silicon MEMS sensor is incompatible with the conventional CMOS process. Therefore, fabricating high aspect ratio deep isolation trenches (about 3μm wide, about 100μm deep) is a urgent process problem. We have fabricated high aspect ratio deep electric isolation trenches (3.6μm wide, 85μm deep) using deep RIE,thermal oxidation and polysilicon refill technology. This paper also adopted a new method to tailor the profile of the open part of deep trench. The open part of deep trench can be largened using RIE after the DRIE process in order to avoid void in the trench.