Protective coating for microelectromechanical systems (MEMS)

"Microelectromechanical systems (MEMS) devices, though built using semiconductor equipment, have a different set of failure mechanisms and reliability concerns than integrated circuits. One major concern is stiction, a term that describes the propensity oftwo silicon surfaces to stick to each other if they touch.To solve this problem, AST is proposing to develop organic coatings with Teflon-like characteristics and a high degree of conformality. The proposed film will be around 200 ¿ thick, uniform over a 12 inch diameter circle, and pinhole free. AST will usedifferent technologies such as Chemical Vapor Deposition (CVD) and Plasma Enhanced Chemical Vapor Deposition (PECVD) to develop robust and durable coating processes for MEMS devices. One method that will be used is the deposition of parylene by the CVDtechnique, with simultaneous fluorination of the deposited film. Another deposition method will be PECVD. The precursor materials for this process will be fluorinated gases such as tetra-fluoro-ethylene or other gases that contain fluorine. Differentfluorinated gases will be tested during the Phase I program in order to optimize thin film characteristics. AST has experience with both methods of deposition, which are used in our commercial products. A thin, uniform, and pinhole free film with Teflon-like properties will very useful for the MEMS industry, and any other industry or government agencies that need a conformal, hyd