MASKING PROCESS FOR FABRICATING ULTRA-HIGH ASPECT RATIO, WAFER-FREE MICRO-OPTO-ELECTROMECHANICAL STRUCTURES

摘要

A masking process resulting from a modified version of the SCREAM process is used for the fabrication of ultra-high aspect ratio, wafer-free, single crystal silicon movable micromechanical devices and frame structures (32) of large vertical depth and narrow linewidth. The process is single-mask, self-aligned and allows the formation of releasable three-dimensional frame-like objects of arbitrary shape which can be made up to about half the wafer thickness in depth and can be subsequently lifted off the substrate and placed on any other material to be used as a mask or to be integrated with other devices. The process consists of a single lithography step and a repeated sequence of thermal oxidations and reaction ion etchings.