论文信息 - Advances in processing techniques for silicon micromechanical devices with smooth surfaces

Advances in processing techniques for silicon micromechanical devices with smooth surfaces

The use of fine-grained polysilicon in the development of micromechanical devices (e.g. bearings, with smooth surfaces) is discussed. Fine-grained polysilicon can be produced with surface roughness near 8 AA r.m.s. (root mean square). The ability to anneal films of this type into tension eliminates size restrictions which are caused by compressive buckling. The use of these films in micromechanical devices has been restricted because hydrogen-fluoride-etched structures are covered by an etch residue which leads to contact welding. Contact between opposing surfaces is induced mainly by surface tension effects. This problem can be avoided by removing the deflection mechanism. Thus, freezing of a water-methanol rinse after sacrificial etching all but eliminates surface tension. Removal of the ice mixture via sublimation at 0.15 mbar occurs readily. Free-standing structures with smooth surfaces and small gaps are then passivated by silicon nitride deposition or other techniques.<<ETX>>

[1] Wafer Bonding for Soi , 1987 .

[2] E. Irene,et al. An in situ Study of Aqueous HF Treatment of Silicon by Contact Angle Measurement and Ellipsometry , 1988 .

[3] D. W. Burns,et al. Mechanical properties of fine grained polysilicon-the repeatability issue , 1988, IEEE Technical Digest on Solid-State Sensor and Actuator Workshop.

[4] R. Muller,et al. Pin joints, gears, springs, cranks, and other novel micromechanical structures , 1987 .

[5] S. Stiffler,et al. Silicon-on-insulator (SOI) by bonding and ETCH-back , 1985, 1985 International Electron Devices Meeting.

[6] M. Shimbo,et al. Silicon‐to‐silicon direct bonding method , 1986 .

[7] D. W. Burns,et al. Fine-grained polysilicon films with built-in tensile strain , 1988 .

[8] R. D. Lillquist,et al. Silicon and Silicon Dioxide Thermal Bonding , 1987 .

[9] M. Mehregany,et al. Integrated fabrication of polysilicon mechanisms , 1988 .

[10] D. W. Burns,et al. Processing conditions for polysilicon films with tensile strain for large aspect ratio microstructures , 1988, IEEE Technical Digest on Solid-State Sensor and Actuator Workshop.

[11] W. Kern,et al. Low-pressure chemical vapor deposition for very large-scale integration processing—A review , 1979, IEEE Transactions on Electron Devices.