MEMS and Nanotechnology Exchange
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- The image is a colorized Scanning Electron Micrograph
(SEM) of a high-aspect ratio MEMS device fabricated out of
single-crystal silicon by the MEMS and Nanotechnology
Exchange fabrication
network. The device itself is made from a
Silicon-On-Insulator (SOI) wafer where a relatively thick
single-crystal silicon device layer (shown in yellow and blue
in the image) has been etched into a complex micromechanical
element that can move under force. The underlying area,
shown in red in the image, is the SOI handle wafer which also
has been etched to form a circular hole completely through
the substrate. This image demonstrates the complexity of
micromechanical devices that can be realized using the MEMS
and Nanotechnology
Exchange.
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- This whimsical image is a colorized Scanning Electron
Micrograph (SEM) of mechanical gear which is smaller than a
human hair. The gear was made polycrystalline silicon using
surface micromachining techniques and is no longer attached
to the substrate. However, the gear did eventually lodge
onto an electrical bond pad (shown in green) due to surface
forces. This image illustrates the extraordinary capability
of MEMS technology to enable the realization of extremely
small mechanical elements. This device was made through
the MEMS and Nanotechnology Exchange fabrication network.
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- The image is a colorized Scanning Electron Micrograph
(SEM) of a salient-pole electrostatically actuated micromotor
made from polycrystalline silicon using surface
micromachining techniques. The central rotating element of
the motor (e.g., the rotor) is the circular structure in
the middle (shown in blue) held to the substrate by the
central bearing (which is shown in red). Properly phased
voltage potentials are placed on the motor stators (typically
120 degrees advanced in phase sequentially around the
stators), which are equally spaced around the perimeter of
the rotor (also shown in blue) and these applied voltages on
the stators cause the central rotor to turn around the
bearing at extremely high angular velocities. This device
was made through the MEMS and Nanotechnology Exchange fabrication
network.
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- "The image is a colorized Scanning Electron Micrograph (SEM)
of microstructure made using extremely short wavelength
exposure techniques of a thick radiation sensitive polymer
layer which was spun onto the substrate and developed after
exposure to reveal an extraordinarily high aspect ratio
microstructure. The central post (shown in orange) is hundreds
of microns tall and only a few microns in diameter. The
surrounding angular shaped structures are also a few microns
wide, separated from one another by a few microns, and are
also hundreds of microns tall. This structure was made
through the MEMS and Nanotechnology Exchange fabrication network.
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- Deep reactive ion etching is a process used to etch substrates
to form deep cavities with relatively high aspect ratio (10-20).
Most Deep RIE systems use the so-called "Bosch process" in which
a fluor polymer is used to passivate the etching of the sidewalls.
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- LIGA stands for X-ray LIthography, Electroforming (German:
Galvanoformung), and molding (German: Abformung). This technology
allows us to define high aspect ratio structures in nickel. The
process consists of exposing a sheet of PMMA bonded to a wafer
using X-ray lithography. The PMMA is then developed and the
exposed material is removed. Nickel is then electroplated up in
the open areas of the PMMA. The nickel over-plate is removed by
polishing, leaving high aspect ratio nickel parts. The PMMA is
removed, and the nickel parts may remain anchored to the substrate
or be released.
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- A MEMS Exchange Information Image