RIE process for fabricating submicron, silicon electromechanical structures
AssigneeCornell Research Foundation, Inc.
InventorsNoel C. MacDonald, Zuoying L. Zhang
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Abstract
A reactive ion etching process is used for the fabrication of submicron, single crystal silicon, movable mechanical structures and capacitive actuators. The reactive ion etching process gives excellent control of lateral dimensions while maintaining a large vertical depth in the formation of high aspect-ratio freely suspended single crystal silicon structures. The silicon etch process is independent of crystal orientation and produces controllable vertical profiles.
Claims7
A reactive ion etching process for the fabrication of submicron, single crystal released structures, comprising:
- forming a wafer from which a single crystal structure is to be fabricated;
- forming an etch mask on a top surface of said wafer;
- transferring to said etch mask by reactive ion etching in a CHF.sub.3 plasma a pattern defining a structure to be formed in said wafer;
- transferring said pattern by a Cl.sub.2 /BCl.sub.3 reactive ion etching from said etch mask to said wafer to form vertical walls defining trenches and steps in said pattern in said wafer;
- selectively masking said vertical walls to define structures to be released in said wafer;
- and
- releasing said selected structures in said wafer using an SF.sub.6 /O.sub.2 reactive ion etching process to completely undercut said selected structures.
A reactive ion etching process for fabricating a high aspect ratio, submicron, released, single crystal electromechanical structure independently of crystal orientation, comprising:
- forming a patterned etch mask on a top surface of a single crystal substrate, the etch mask defining a structure of arbitrary shape to be formed in said substrate;
- transferring the pattern of said etch mask by reactive ion etching to said substrate to form trenches defining the structure to be formed in the substrate, said etching step forming trenches having bottom walls and vertical side walls;
- forming an electrically insulating layer on exposed surfaces of said substrates, including the vertical side walls of said trenches;
- forming metal electrodes on selected portions of said vertical side walls;
- and
- reactive ion etching the bottom walls of said trenches to undercut and to release said defined structure to thereby produce a movable, high aspect ratio released single crystal structure having vertical side walls.
Dependencies are inferred from the claim text.