Method for forming suspended micromechanical structures
- Albuquerque, NM
A micromachining method is disclosed for forming a suspended micromechanical structure from {111} crystalline silicon. The micromachining method is based on the use of anisotropic dry etching to define lateral features of the structure which are etched down into a {111}-silicon substrate to a first etch depth, thereby forming sidewalls of the structure. The sidewalls are then coated with a protection layer, and the substrate is dry etched to a second etch depth to define a spacing of the structure from the substrate. A selective anisotropic wet etchant (e.g. KOH, EDP, TMAH, NaOH or CsOH) is used to laterally undercut the structure between the first and second etch depths, thereby forming a substantially planar lower surface of the structure along a {111} crystal plane that is parallel to an upper surface of the structure. The lateral extent of undercutting by the wet etchant is controlled and effectively terminated by either timing the etching, by the location of angled {111}-silicon planes or by the locations of preformed etch-stops. This present method allows the formation of suspended micromechanical structures having large vertical dimensions and large masses while allowing for detailed lateral features which can be provided by dry etch definition. Additionally, the method of the present invention is compatible with the formation of electronic circuitry on the substrate.
- Research Organization:
- SANDIA CORP
- DOE Contract Number:
- AC04-94AL85000
- Assignee:
- Sandia Corporation (Albuquerque, NM)
- Patent Number(s):
- US 6020272
- OSTI ID:
- 872838
- Country of Publication:
- United States
- Language:
- English
Free standing single-crystal silicon microstructures
|
journal | March 1995 |
Anisotropic etching of (111)-oriented silicon and applications
|
conference | August 1998 |
Similar Records
Micromachined cutting blade formed from {211}-oriented silicon
Micromachined cutting blade formed from {211}-oriented silicon
Related Subjects
/438/216/
111
additionally
allowing
allows
angled
anisotropic
based
circuitry
coated
compatible
controlled
crystal
crystal plane
crystalline
crystalline silicon
csoh
define
definition
depth
depths
detailed
dimensions
disclosed
dry
dry etching
edp
effectively
electronic
electronic circuit
electronic circuitry
etch
etch-stops
etchant
etched
etching
extent
features
formation
forming
koh
lateral
lateral extent
laterally
layer
location
locations
machining method
masses
mechanical structure
method
method allow
method allows
micromachining
micromachining method
micromechanical
micromechanical structure
micromechanical structures
naoh
parallel
planar
plane
planes
preformed
protection
provided
selective
sidewalls
silicon
silicon substrate
spacing
structure
structures
substantially
substantially planar
substrate
surface
suspended
suspended micromechanical
terminated
timing
tmah
undercut
undercutting
upper
upper surface
vertical
vertical dimension
wet