A microfluidics based targeted etchant delivery and masking approach to wet etching has been used to control the etch
progression of a MEMS sacrificial layer during the release of silicon nitride (SiNx) microbeams. A reusable 3-input
open-channel polydimethylsiloxane (PDMS) microfluidic cassette was used to form a dynamically controllable fluid etch
mask to control the location of the etchant during the wet release process. In contrast conventional release techniques
which use solid masking and homogeneous etching environments, microfluidic devices can utilise laminar flows to
generate heterogeneous etching conditions which can be controlled in real-time by altering the composition and flow
rates of the fluids passing through specific inlets. The fluid nature of the heterogeneous flow can be used to target etch
specific areas of sacrificial material or conversely, dynamically mask specific areas both above and below suspend
structures. As a result of this control, structures with anchor geometries not achievable using conventional release
techniques were created. Not only does this method require small volumes of etchant fluid, it is also suitable for use on
samples which may be sensitive to the chemical and/or physical rigors of photolithographic patterning, such as porous
silicon. Microfluidic based release etching, using dynamically controlled fluid masks, provides a valuable addition to the
suite of microchannel based fabrication techniques.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.