Skip to main content Accessibility help
×
Home

Selective W for Coating and Releasing MEMS Devices

  • S. S. Mani (a1), J. G. Fleming, J. J. Sniegowski, M. P. de Boer, L. W. Irwin, J. A. Walraven, D. M. Tanner and D. A. La Van...

Abstract

Two major problems associated with Si-based MEMS (MicroElectroMechanical Systems) devices are stiction and wear. Surface modifications are needed to reduce both adhesion and friction in micromechanical structures to solve these problems. In this paper, we will present a CVD (Chemical Vapor Deposition) process that selectively coats MEMS devices with tungsten and significantly enhances device durability. Tungsten CVD is used in the integrated-circuit industry, which makes this approach manufacturable. This selective deposition process results in a very conformal coating and can potentially address both stiction and wear problems confronting MEMS processing. The selective deposition of tungsten is accomplished through the silicon reduction of WF6. The self-limiting nature of this selective W deposition process ensures the consistency necessary for process control. The tungsten is deposited after the removal of the sacrificial oxides to minimize stress and process integration problems. Tungsten coating adheres well and is hard and conducting, requirements for device performance. Furthermore, since the deposited tungsten infiltrates under adhered silicon parts and the volume of W deposited is less than the amount of Si consumed, it appears to be possible to release stuck parts that are contacted over small areas such as dimples. The wear resistance of selectively coated W parts has been shown to be significantly improved on microengine test structures.

Copyright

References

Hide All
1. Howe, R. T. and Muller, R. S., J. Electrochem Soc: Solid State Science & Technology, 103(6) p. 1420 (1983).
2. Garcia, E. J. and Sniegowski, J. J., Sensors and Actuators A, 48, p. 203 (1995).
3. Miller, S. L., Sniegowski, J. J., LaVigne, G., and McWhorter, P. J. in Proceedings of SPIE Smart Electronics and MEMS 2722, p. 197 (1996).
4.Danelle Tanner, M., Miller, W. M., Eaton, W. P., Irwin, L. W., Peterson, K. A., Dugger, M. T., Senft, D. C., Smith, N. F., Tangyunyong, P., and Miller, S. L. in 1998 IEEE International Reliability Physics Proceedings, p. 26 (1998).
5. Tanner, Danelle M., Walraven, Jeremy A., Irwin, Lloyd W., Dugger, Michael T., Smith, Norman F., Miller, William M., and Miller, Samuel L. in Proc. Of IEEE International Reliability Physics Symposium, p. 189 (1999).
6. Deng, K., Collins, R. J., Mehrengany, M. and Sukenik, C. N., J. Elctrochem. Soc., 142(4), p. 1278 (1995).
7. Srinivasan, U., Houston, M. R., Howe, R. T. and Maboudian, R., J. Micromech. Sys., 7(2), p. 252 (1998).10.1109/84.679393
8. Bradbury, D. R., Turner, J. E., Nauka, K. and Chiu, K. Y., IEDM, p. 273, (1991).
9. Sekine, M., Kakuhara, Y., Yamazaki, K. and Murao, Y., MRS Advanced Metallization ULSI Applications, p. 255, (1991).
10. Yu, M. L., Eldridge, B. N., and Joshi, R. V., in Deposition and Growth: Limits for Microelectronics, edited by Rubloff, G. W. (AIP Conf. Proc. 167, New York 1988), p. 202.
11. Broadbent, E. K. and Ramiller, C. L., J Elctrochem. Soc.: Solid-State Science and Techonolgy, 131(6), p. 1427 (1984).
12. Green, M. L and Levy, R. A., J Elctrochem. Soc.: Solid-State Science and Techonolgy, 132(5), p. 1243 (1985).
13. Yu, M. L., Eldridge, B. N., and Joshi, R. V., in Tungsten and Other Refractory Metals for VLSA Applications III, edited by Wells, V. A. (MRS Proc. Pittsburgh, PA), 1988, p. 75.
14. Kepten, A., Reisman, A., Ray, M., SMith, P. L., Temple, D., and Tapp, F., J. Electrochem. Soc, 139(8), p. 2331 (1992).
15. Mani, S. S., Fleming, J. G, and Sniegowski, J. J. in Proceedings of SPIE, Micromachining anc Microfabrication Process Technology V, 3874, p. 150 (1999).
16. Miller, S. L., Sniegowski, J. J., LaVigne, G., and McWhorter, P. J. in Proceedings of SPIE Micromachined Devices and Components II, 2882, p. 182 (1996).10.1117/12.250702
17. Smith, Norman F., Eaton, William P., Tanner, Danelle M., and Allen, James J. in SPIE Proceedings, 3880, p. 156 (1999).
18. Miller, S. L., Rodgers, M. S., LaVigne, G., Sniegowski, J. J., Clews, P., Tanner, D. M., Peterson, K. A. in Proc. Of IEEE International Reliability Physics Symposium, p. 17 (1998).
19. LaVan, D. A. and Buchheit, T. E. in Symposium MM Materials Science of MicroElectroMechanical System (MEMS) Devices 11, Proceedings of the 1999 MRS Fall Meeting Dec 1-3 1999 Boston.

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed