STICTION OF SURFACE MICROMACHINED STRUCTURES AFTER RINSING AND DRYING- MODEL AND INVESTIGATION OF ADHESION MECHANISMS

The mechanisms causing stiction of polysilicon structures fabricated b y surface micromachining techniques have been investigated. It is foun d that during drying from rinse,liquids attractive dynamic capillary f orces are responsible for bringing micromechanical structures into con tact with the underlying substrate. Measured adhesion energies of stic king microbridges indicate that van der Waals forces are responsible f or the stiction of hydrophobic surfaces and that hydrogen bridging is an additional adhesion mechanism for hydrophilic surfaces. Methods to reduce the stiction problem are indicated.