SINGLE HIGH ASPECT RATIO PILLAR SUPPORT STRUCTURES: Multi-scale Chip Integrated Conformal Structures

摘要

This paper describes the realization of the integration of micro and nanoscale conformal structures. A new dry processing technique is used to create structures supported by a single high aspect ratio pillar support (SHARPS), creating submicron single crystal silicon features, with tight geometric control, attached to much larger (10-200μm) silicon dioxide platforms. The platforms have lithographically defined two dimensional shapes. The curvature of the platforms is adjusted through metal deposition and subsequent processing. The flexibility of the structures allows them to conform to meso and microscale roughness. To account for nanoscale conformance stochastic arrays of vertically aligned titania nanofibers are created on the platform surface. The application of the system as a passive microadhesive is investigated using a nanoindenter. Results show that the titania nanofiber surface offers significant increase in adhesion over smooth silicon dioxide or titanium surfaces. However when used in conjunction with the SHARPS structures the fibers are too stiff to allow for conformance to the surface prior to larger scale conformation, thus the combination does not increase the overall adhesion.