**Part 2**

**MEMS Characterization and Micromachining** 

86 Microelectromechanical Systems and Devices

Vellekoop, N. J., Jakoby, B., & Bastemeijer, J. (1999).*A Love-wave ice detector.* Proceedings of

Vetelino, K. A., Story, P. R., Mileham, R. D., & Galipeau, D. W. (1996). Improved dew point

Visser, J. H., Vellekoop, M. J., Venema, A., Drift, E. v. d., Rek, P. J. M., & Nederhof, A. J.

Weber, J., Albers, W. M., Tuppurainen, J., Link, M., Gabl, R., Wersing, W., et al. (2006). Shear

Weigel, R., Morgan, D. P., Owens, J. M., Ballato, A., Lakin, K. M., Hashimoto, K., et al.

White, R. M., & Voltmer, F. W. (1965). Direct piezoelectric coupling to surface elastic waves.

Wingqvist, G., Bjurstrom, J., Liljeholm, L., Katardjiev, I., & Spetz, A. L. (2005).*Shear mode AlN* 

Wohltjen, H., & Dessy, R. (1979). Surface acoustic wave probe for chemical analysis. I.

Zhang, X., Xu, W., Abbaspour-Tamijani, A., & Chae, J. (2009).*Thermal Analysis and* 

Zuo, C., Van der Spiegel, J., & Piazza, G. (2010). 1.05-GHz CMOS Oscillator Based on

Zhou, W. (2009). *Integration of MEMS Resonators within CMOS Technology.* Cornell.

*on Microwave Theory and Techniques,* Vol. *50*, No. 3, (2002), pp. 738-749. Weld, C. E., Sternhagen, J. D., Mileham, R. D., Mitzner, K. D., & Galipeau, D. W.

measurements based on a SAW sensor. *Sensors and Actuators B: Chemical,* Vol. *35*,

(1989).*Surface Acoustic Wave filter in ZnO-SiO2-Si layered structures.* Proceedings of

mode FBARs as highly sensitive liquid biosensors. *Sensors and Actuators A: Physical,* 

(2002). Microwave acoustic materials, devices, and applications. *IEEE Transactions* 

(1999).*Temperature measurement using surface skimming bulk waves.* Proceedings of

*thin film electroacoustic resonator for biosensor applications.* Proceedings of IEEE

Introduction and instrument description. *Analytical Chemistry,* Vol. *51*, No. 9,

*Characterization of a High Q Film Bulk Acoustic Resonator (FBAR) as Biosensors in Liquids.* Proceedings of IEEE 22nd International Conference on MEMS, pp. 939-942.

Lateral-Field-Excited Piezoelectric AlN Contour-Mode MEMS Resonators. *Chengjie* 

IEEE Ultrasonics Symposium, ISBN 1051-0117, 1999

No. 1-3, (1996), pp. 91-98,

IEEE Ultrasonics Symposium.

Vol. *128*, No. 1, (2006), pp. 84-88.

Sensors, Oct. 30 2005-Nov. 3 2005

(1979), pp. 1458-1464.

*Zuo,* Vol., No. (2010), pp. 15.

IEEE Ultrasonics Symposium, 1051-0117, 1999.

*Applied Physics Letters,* Vol. *7*, No. (1965), pp. 314-316,

**5** 

**MEMS Characterization Based on** 

Micro Electro Mechanical Systems (MEMS) is developed based on the semi-conductor technology, however, relative material, design, fabrication, simulation, packaging and test are more complex than those in semi-conductor technology. In the primary stage, MEMS technology focused on the design and development, now on the commercialization and improving reliability and decreasing cost and price. So test is increasingly important to MEMS technology and testing cost is about 1/3 of the whole cost of MEMS. In order to improve the production and decrease the cost, producers and researchers pay more attention to MEMS test to solve all the testing problems from design to packaging process. There are a number of methods to carry out these measurements, such as scanning electron microscopy (SEM), atomic force microscopy (AFM), stylus profiler, and optical profiler, etc.

 SEM is one of the most common measurement tools. However, nearly all nonconductive specimens examined using SEM need to be coated with a thin film of conducting material. This may result in bending or distortion of the device, especially where free structures such as cantilever beams. SEM tests are also time consuming and

 AFM has been suggested as a MEMS measurement tool. As with SEM, analysis may be slow (about 20 min/device), and the limited measurement range of an AFM (100 μm×100 μm×5 μm, Veeco multimode AFM) means that it is unable to investigate large samples or out-of-plane devices such as the cantilevers. It is also difficult to examine

 Mechanical stylus surface profilers are commonly used for dimensional measurements in MEMS. While these can measure step heights with a high accuracy, they are not suitable for the analysis of freestanding structures, where the stylus may break the device under test. Deep, high aspect ratio devices also pose problems, as the stylus

If MEMS devices need to fit the large-scale production, it is essential that these measurements must be cheaply and easily made at the wafer level, without the need for large space, expensive packaging or destructive test methods. Optical techniques can offer

probe may be too large to accurately reproduce the surface profile.

**1. Introduction** 

Every method has its advantages and disadvantages.

not suitable for a production environment.

packaged devices using an AFM.

**Optical Measuring Methods** 

*3Tianjin University of Technology and Education* 

Tong Guo1, Long Ma2 and Yan Bian3

*2Civil Aviation University of China* 

*1Tianjin University* 

*P.R. China* 
