基于光谱反射技术的梯形刻面MEMS高深宽比沟槽深度测量仿真分析  

Simulation Analysis for Depth Measurement of the MEMS High Aspect Ratio Trenches with the Trapezoidal Facet Based on Spectral-reflectometry

作　　者：杨楠卓 欧阳名钊[1] 周维虎 陈晓梅 YANG Nan-zhuo;OUYANG Ming-zhao;ZHOU Wei-hu;CHEN Xiao-mei(School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022;Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029)

机构地区：[1]长春理工大学光电工程学院,长春130022 [2]中国科学院微电子研究所,北京100029

出　　处：《长春理工大学学报（自然科学版）》2020年第2期48-52,114,共6页Journal of Changchun University of Science and Technology(Natural Science Edition)

基　　金：国家重点研发计划项目(2018YFB2003403)。

摘　　要：高深宽比沟槽是一种重要的微机电系统(MEMS)结构,沟槽的加工刻蚀过程中,由于工艺的影响会在沟槽顶部出现期望之外的梯形刻面,其对深度的测量将造成影响。基于光谱反射技术对深宽比20∶1、标称深度100μm且具有梯形刻面的沟槽深度测量进行了仿真分析;并基于离散傅里叶变换(DFT)仿真分析了梯形刻面面积和梯形刻面粗糙度对测量结果的影响:梯形刻面面积越大,DFT图像峰值越小;刻面粗糙度越大,DFT图像峰值越小。同时,分析了沟槽底部形貌造成的噪声影响,并通过将沟槽近似为台阶结构的方法得出了沟槽面积与深度峰值的关系。本研究可以为MEMS沟槽结构加工中出现的测量误差提供必要的理论指导,帮助提高MEMS沟槽结构的加工精度。High aspect ratio trench is an important micro-electromechanical system(MEMS) structure. In the process of trench etching,unwanted trapezoidal facet would appear on the top of trench,due to the influence of process technology,which will affect the depth measurement. In this paper,spectral-reflectometry is used to measure the depth of trenches with trapezoidal facet,the structure with an aspect ratio of 20:1 and depth of 100 μm is simulated measured by the designed measuring system. And the influence of trapezoidal facet area and trapezoidal facet roughness on measurement results is analyzed:the peak value of DFT image decreases with the increase of trapezoidal facet area and the increase of facet roughness. By approximating the trench to a step structure,the noise effect caused by the trench bottom morphology is analyzed,the relationship between trench area and depth peak is obtained. This study can provide the necessary theoretical guidance for the processing errors of MEMS trench structure,and help to improve the processing accuracy of MEMS trench structure.

关 键 词：MEMS 光谱反射技术 离散傅里叶变换 

分 类 号：O433.1[机械工程—光学工程]