Stiction or adhesion between the substrate (usually silicon based) and the microstructure occurs
during the isotropic wet etching of the sacrificial layer. The capillary forces due to the surface
tension of the liquid between the microstructure and substrate during drying of the wet etchant
cause the two surfaces to adhere together. Separating the two surfaces is often complicated due
to the fragile nature of the microstructure. Stiction is often circumvented by the use of a
sublimating fluid (often supercritical CO2, which has extremely low surface tension) drying
process where the liquid phase is bypassed. CO2 displaces the rinsing fluid and is heated past the
supercritical point. As the chamber pressure is slowly released the CO2 sublimates thereby
preventing stiction.
Solution
Stiction or adhesion between the substrate (usually silicon based) and the microstructure occurs
during the isotropic wet etching of the sacrificial layer. The capillary forces due to the surface
tension of the liquid between the microstructure and substrate during drying of the wet etchant
cause the two surfaces to adhere together. Separating the two surfaces is often complicated due
to the fragile nature of the microstructure. Stiction is often circumvented by the use of a
sublimating fluid (often supercritical CO2, which has extremely low surface tension) drying
process where the liquid phase is bypassed. CO2 displaces the rinsing fluid and is heated past the
supercritical point. As the chamber pressure is slowly released the CO2 sublimates thereby
preventing stiction..
Stiction or adhesion between the substrate (usually silicon based) a.pdf
1. Stiction or adhesion between the substrate (usually silicon based) and the microstructure occurs
during the isotropic wet etching of the sacrificial layer. The capillary forces due to the surface
tension of the liquid between the microstructure and substrate during drying of the wet etchant
cause the two surfaces to adhere together. Separating the two surfaces is often complicated due
to the fragile nature of the microstructure. Stiction is often circumvented by the use of a
sublimating fluid (often supercritical CO2, which has extremely low surface tension) drying
process where the liquid phase is bypassed. CO2 displaces the rinsing fluid and is heated past the
supercritical point. As the chamber pressure is slowly released the CO2 sublimates thereby
preventing stiction.
Solution
Stiction or adhesion between the substrate (usually silicon based) and the microstructure occurs
during the isotropic wet etching of the sacrificial layer. The capillary forces due to the surface
tension of the liquid between the microstructure and substrate during drying of the wet etchant
cause the two surfaces to adhere together. Separating the two surfaces is often complicated due
to the fragile nature of the microstructure. Stiction is often circumvented by the use of a
sublimating fluid (often supercritical CO2, which has extremely low surface tension) drying
process where the liquid phase is bypassed. CO2 displaces the rinsing fluid and is heated past the
supercritical point. As the chamber pressure is slowly released the CO2 sublimates thereby
preventing stiction.
