Elimination of post-release adhesion in microstructures using conformal fluorocarbon coatings

Author

Man, Piu Francis ; Gogoi, Bishnu P. ; Mastrangelo, Carlos H.

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA

Volume

6

Issue

1

fYear

1997

fDate

3/1/1997 12:00:00 AM

Firstpage

25

Lastpage

34

Abstract

The adhesion of polysilicon microstructures to their substrates is eliminated using a relatively conformal hydrophobic fluorocarbon (FC) coating grown in a field-free zone of a plasma reactor. Experiments show that the FC film deposition on top of the microstructure and on the underside was approximately 2:1. The FC coating is able to cover the entire underside of a 200×200 μm² plate, with a 20% deposition nonuniformity. The coating exhibits a contact angle of 110° and is able to prevent adhesion of cantilever beams and doubly supported beams to their substrates even after direct immersion in DI water. The durability of the coating was tested using an accelerated aging method, predicting a lifetime of greater than ten years at 150°C. Periodic wear tests indicate that the coating remains hydrophobic even after 10⁷ contact cycles

Keywords

adhesion; ageing; conformal coatings; contact angle; micromechanical devices; plasma deposited coatings; polymer films; wear; DI water immersion; Si; accelerated aging; adhesion; cantilever beam; conformal hydrophobic fluorocarbon coating; contact angle; contact cycle; doubly supported beam; durability; lifetime; periodic wear; plasma polymerization; polysilicon microstructure; Adhesives; Coatings; Force sensors; Inductors; Life testing; Microstructure; Plasma properties; Polymer films; Structural beams; Substrates;

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/84.557527

Filename

557527