Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-27T23:57:27.381Z Has data issue: false hasContentIssue false

Strength of Surface Micromachined Diaphragms

Published online by Cambridge University Press:  10 February 2011

Xing Yang
Affiliation:
Caltech Micromachining Laboratory, 136-93, Electrical Engineering California Institute of Technology, Pasadena, CA 91125, [email protected]
Frances M. Siu
Affiliation:
Caltech Micromachining Laboratory, 136-93, Electrical Engineering California Institute of Technology, Pasadena, CA 91125
Yu-Chong Tai
Affiliation:
Caltech Micromachining Laboratory, 136-93, Electrical Engineering California Institute of Technology, Pasadena, CA 91125
Get access

Abstract

This paper presents the study of the strength of surface micromachined diaphragms. It is found that the diaphragm strength strongly depends on the diaphragm boundary conditions. A new fabrication technique which does not change the mask and fabrication process is proposed to improve the common step-up boundary condition. Test diaphragms with diameters from 200 µm to 800 µm and three different boundary conditions have been fabricated using silicon nitride/PSG and silicon nitride/polysilicon surface micromachining processes. Experimentally, it is found that the strength of the diaphragms is significantly improved with the new boundary conditions. The application of this technique to other surface micromachined structures is also described.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Timoshenko, S. and Woinowsky-Krieger, S., Theory of Plates and Shells, McGraw-Hill, New York, 1959.Google Scholar
2 Guckel, H., Randazzo, T. and Burns, D. W., Journal of Applied Physics, 57, 1671 (1985).Google Scholar
3 Howe, R. T. and Muller, R. S., Journal of Electrochemical Society, 130, 1420 (1983).Google Scholar
4 Mullen, R. L., Mehregany, M., Omar, M. P., and Ko, W. H., “Theoretical Modeling of Boundary Conditions in Microfabricated Beams”, Proceedings of IEEE Workshop on Micro Electro Mechanical Systems, Nara, Japan, February, 1991, pp. 154159.Google Scholar
5 Meng, Q., Mehregany, M., and Mullen, R. L., “Analytical Modeling of Step-up Supports in Surface-Micromachined Beams”. Technical Digest. the 7th International Conference on Solid-State Sensors and Actuators, Yokohama, Japan, June 7-10, 1993, pp. 779782.Google Scholar
6 Ngo, L. V., Nelson, P., and Kim, C.-J., “Surface-Micromachined Beams without Spring Effect of Anchor Step-up”, Technical Digest, Solid-State Sensor and Actuator Workshop, Hilton Head Island, South Carolina, 1996, June 3-6, pp. 140143.Google Scholar
7 Liu, J., Tai, Y.-C., Lee, J., Pong, K. C., Zohar, Y., and Ho, C.-M., “In Situ monitoring and universal modeling of sacrificial PSG etching using hydrofluoric acid”, Proceedings of IEEE Workshop on Micro Electro Mechanical Systems, Fort Lauderdale, Florida, February, 1993, pp. 7176.Google Scholar
8 Tabata, O., Funabashi, H., Shimaoka, K., Ashhi, R. and Sugiyama, S., “Surface Micromachining Using Polysilicon Sacrificial Layer”, the 2nd International Symposium on Miromachine and Human Science, Nagoya, Japan, October 8-9, 1991, pp. 163172.Google Scholar
9 Yang, X., Tai, Y.-C. and Ho, C.-M., “Micro Bellow Actuators”, Technical Digest. the 9th International Conference on Solid-State Sensors and Actuators, Chicago, IL, June 16-19, 1997, pp. 4548.Google Scholar