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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The wet etch will not work due to undercut. Has for RIE you would need a high density ICP type etch tool, I think ULVAC sells such a tool. 500um of SiO2 is a tall order good luck.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Rick<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Richard Morrison<o:p></o:p></p>
<p class="MsoNormal">DMTS<o:p></o:p></p>
<p class="MsoNormal">Draper Laboratory<o:p></o:p></p>
<p class="MsoNormal">555 Technology Square<o:p></o:p></p>
<p class="MsoNormal">Cambridge Ma 02139<o:p></o:p></p>
<p class="MsoNormal">Office: 617-258-3420<o:p></o:p></p>
<p class="MsoNormal">Cell: 508-930-3461<o:p></o:p></p>
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<p class="MsoNormal"><b>From:</b> labnetwork <labnetwork-bounces@mtl.mit.edu> <b>
On Behalf Of </b>Ningzhi Xie<br>
<b>Sent:</b> Wednesday, January 18, 2023 4:23 PM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [EXTERNAL] [labnetwork] Deep anisotropic etching of SiO2<o:p></o:p></p>
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<p class="MsoNormal"> Dear college, <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">We want to perform a highly anisotropic, very deep (~500um) etching of SiO2 with a vertical side wall. On top of the SiO2 is nanostructures protected by photoresist. The etch depth needs to be controlled with a precision of 20% (we are
thinking of using another material as the substrate underneath the SiO2 layer, which acts as an etch-stopper). The structure and dimensions are shown in the attached image. It would be very helpful if anyone has any idea of this kind of etching (either dry
and wet chemical etch is fine).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thank you very much.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Best regards, <o:p></o:p></p>
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<p class="MsoNormal">Ningzhi Xie<o:p></o:p></p>
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<p class="MsoNormal">Department of Electrical and Computer Engineering<o:p></o:p></p>
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<p class="MsoNormal">University of Washington<o:p></o:p></p>
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