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<div class="moz-cite-prefix">KOH bath is electro-polished stainless
steel extruded (soft corners) vessel. <br>
Heated via an immersion heater, controlled by a PID controller. <br>
Thermocouple and backup OT thermocouples are internal to the bath,
<br>
Type J with PFA cladding. Bath has lid, no reflux. <br>
<br>
We sparge KOH bath with O2 to react with generated H2 and minimize
hillock formation<br>
J. Micromech. Microeng. 9 (1999) 139–145.<br>
<br>
Members mix their own KOH, use for period of hours, can reserve
for up to<br>
2 days, then dispose. KOH is mixed from solid source with DI so
material<br>
cost is modest compared to CMOS grade acid bath<br>
<br>
<br>
Bill Flounders<br>
UC Berkeley NanoLab<br>
<br>
<br>
<br>
Tony L Olsen wrote:<br>
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<p class="MsoNormal">Dear Labnetwork<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We are building a new wet bench and would
like to include a dedicated KOH etch bath to replace the
current methodology of glassware with stir bars on a
hotplate. We generally use a bath of 80°C.<o:p></o:p></p>
<p class="MsoNormal">Our wetbench vendor initially quoted a
recirculated bath in a stainless steel tank. We are concerned
about the stainless, nor do we believe the Teflon or PVDF
wetted surfaces in the proposed diaphragm pump will hold up to
the hot KOH. Another option we are aware of is a quartz tank
heated externally by recirculated water. I’m certain there
are other options, too.<o:p></o:p></p>
<p class="MsoNormal">Can you share your experience with
dedicated KOH baths? What is the configuration? What are the
materials? How do you mix/stir the bath? What problems have
you experienced? What would you do next time?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank You,<o:p></o:p></p>
<p class="MsoNormal">tonyO<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Tony Olsen<o:p></o:p></p>
<p class="MsoNormal">Nanofab Cleanroom Supervisor/Process
Engineer<o:p></o:p></p>
<p class="MsoNormal">36 S Wasatch Dr, Suite 2500 SMBB<o:p></o:p></p>
<p class="MsoNormal">Salt Lake City, UT 84112<o:p></o:p></p>
<p class="MsoNormal">801-587-0651 office<o:p></o:p></p>
<p class="MsoNormal">801-587-3077 fax<o:p></o:p></p>
<p class="MsoNormal"><a moz-do-not-send="true"
href="http://www.nanofab.utah.edu/"><span
style="color:#6666CC">www.nanofab.utah.edu</span></a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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