高频单面无极石英晶体监测二氧化硅的刻蚀

High-frequency Single-side Electrodeless Quartz Crystal Microbalance Monitors the Etching Rate of Silicon Dioxide

研发一种能监测二氧化硅刻蚀的高频单面无极石英晶体微天平(HS-ES-QCM)传感装置,该检测装置是基于单片机控制DDS数字发生器产生正弦波信号对无极石英晶体进行扫描激励,通过相敏检波对其谐振频率信号采集的一种分析系统。H-S-ES-QCM可实现对二氧化硅刻蚀实时监测,其使用工作频率在100 MHz的压电石英晶体作为传感原件,理论上,当H-S-ES-QCM检测系统噪声误差在20 Hz时,灵敏度可达到0.89 ng/cm^(2),检测下限达到3.36×10^(-8) cm。实验结果显示,当厚度变化为1 nm时,对应的近6,000 Hz的频率变化,能够高灵敏地检测到亚纳米级厚度二氧化硅的刻蚀,以及重现性偏差在3%以内,有着优良的重现性,表明了H-S-ES-QCM传感系统在在半导体湿法刻蚀领域中具有推广应用价值。

Developed a high-frequency single-side electrodeless quartz crystal microbalance(H-S-ES-QCM)sensing device that can monitor the etching of silicon dioxide,which is an analysis system based on a microcontroller controls DDS digital generator to generate a sine wave signal to scan and excite the electrodeless quartz crystal,and to collect its resonant frequency signal through a phase sensitive detector H-S-ES-QCM can monitor silicon dioxide etching in real time,it uses a piezoelectric quartz crystal with a working frequency of 100 MHz as the sensing element.Theoretically,when the noise of the H-S-ES-QCM detection system is at 20 Hz,the sensitivity can reach 0.89 ng/cm^(2),the lower detection limit reaches 3.36×10^(-8)cm.The experimental results show that when the thickness change is 1 nm,it causes a frequency change of nearly 6,000 Hz,which can detect the etching of sub-nanometer silicon dioxide with high sensitivity,and the reproducibility deviation is within 3%,which has excellent reproducibility.It showed that the H-S-ES-QCM sensing system has the promotion and application value in the field of semiconductor wet etching.