Real-time monitoring of thickness of silicon membrane during wet etching using a novel surface acoustic wave sensor

Chi-Yuan Lee; Tsung-Tsong Wu; Yung-Yu Chen; Ying-Chou Cheng; Wen-Jong Chen; Shih-Yung Pao; Pei-Zen Chang; Ping-Hei Chen; Kai-Hsiang Yen; Fu-Yuan Xiao

doi:10.1117/12.544959

16 August 2004 Real-time monitoring of thickness of silicon membrane during wet etching using a novel surface acoustic wave sensor

Chi-Yuan Lee, Tsung-Tsong Wu, Yung-Yu Chen, Ying-Chou Cheng, Wen-Jong Chen, Shih-Yung Pao, Pei-Zen Chang, Ping-Hei Chen, Kai-Hsiang Yen, Fu-Yuan Xiao

Author Affiliations +

Proceedings Volume 5455, MEMS, MOEMS, and Micromachining; (2004) https://doi.org/10.1117/12.544959
Event: Photonics Europe, 2004, Strasbourg, France

Abstract

This study presents a novel method based on the surface acoustic wave (SAW) sensor, for monitoring the thickness of a silicon membrane in real time during wet etching. Similar to accelerometers and pressure sensors, some micro-electro-mechanical systems (MEMS) devices require the thickness of silicon membranes to be known precisely. Precisely controlling the thickness of a silicon membrane during wet etching is important, because the thickness strongly affects post-processing and device performance. Moreover, the proposed surface acoustic wave sensor allows the thickness of a silicon membrane to be monitored from a few μm to hundreds of μm in situ, which depends on the periodicity of interdigital transducers (IDT). A novel method, which differs from any in previous work on etch-stop techniques, is developed in-situ for monitoring the thickness of a silicon membrane during wet etching. In summary, the proposed method for measuring the thickness of a silicon membrane in real time, is highly accurate; is simple to implement, and can be mass-produced. This work also describes the principles of the method used, detailed process flows, the method of taking measurements and the simulated and experimental results. The theoretical and measured values differ by an error of less than 2.50μm, so the results closely agree with each other.

Citation Download Citation

Chi-Yuan Lee, Tsung-Tsong Wu, Yung-Yu Chen, Ying-Chou Cheng, Wen-Jong Chen, Shih-Yung Pao, Pei-Zen Chang, Ping-Hei Chen, Kai-Hsiang Yen, and Fu-Yuan Xiao "Real-time monitoring of thickness of silicon membrane during wet etching using a novel surface acoustic wave sensor", Proc. SPIE 5455, MEMS, MOEMS, and Micromachining, (16 August 2004); https://doi.org/10.1117/12.544959

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available