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PCT Systems works alongside our clients to solve real world process problems.
Company: HT Micro
Problem
The diffusion limited nature of normal aqueous etching prohibits the timely
release of many large area structures. Typically, release layer thicknesses
that we encounter are from submicron to several microns. When trying to
under etch structures that are several millimeters or more the etch times
can be many days with etch rates that can ultimately become nearly zero far
into an etch cavity. The use of ultrasonic, besides the big problem of
structure mechanical damage, does not allow coupling into the micron scale
etch cavity.
Solution Strategy
Provide HT Micro with a megasonics system that adequately provides boundary
layer reduction for the etch process along with the correct frequency
acoustics as to not damage the devices.
Results
With the PCT megasonics system the etch rates were found to be largely
constant as a function of undercut depth. The practical significance is an
average undercut acceleration of up to 6X for some of our applications and
the avoidance of so called “etch release holes” – that become unwanted
artifacts of the release process that with megasonics assistance are no
longer required to allow timely release of relatively large area structures.
This has resulted in the realization of structures that could not have been
fabricated without the use of megasonics.
www.htmirco.com
