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Hi Larry,</div>
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As it happens, Cu is not an established ALD process yet (that I am aware of).</div>
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Pt is common, but for your purposes (filling a 20um diameter hole) Pt would likely too expensive. In fact, ALD is probably not a viable option because you will need a layer slightly thicker than the radius of the hole (i.e. 10 um) and ALD of almost anything
in a 10um thickness will take 2-3 weeks (at least in our systems). We tend to speak of dep thickness/cycle (~1A) because to speak of rate in thickness/min is too embarrassing!</div>
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Which is to say, ALD is slow. </div>
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Typical films are under 200nm.</div>
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Material-wise, Pt, Ru, and some other conductors are available, but they tend to be on the (even) slower side. Some newer systems will get cycle times down to achieve 20-30 cy/min, but still nothing approaching CVD growth rates.</div>
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A Pt liner (or other conductive material) with Cu electroplating is much closer to a standard process for this sort of thing. And if you wanted to get fancy you could even consider selective W CVD, but that would require a bit of process development.</div>
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I'm happy to chat about this off-line if you like. Hopefully others with proper electroplating experience will chime in shortly.</div>
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Mac</div>
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Harvard CNS</div>
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<div id="divRplyFwdMsg" dir="ltr"><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> labnetwork <labnetwork-bounces@mtl.mit.edu> on behalf of Hess, Larry A. (GSFC-5530) <larry.hess-1@nasa.gov><br>
<b>Sent:</b> Wednesday, February 26, 2025 9:36 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu <labnetwork@mtl.mit.edu><br>
<b>Subject:</b> [labnetwork] Copper Through-Glass Vias on fused silica</span>
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<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Hi,</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">I am looking for a (hopefully established) source to deposit ALD copper on Though-Glass Vias.</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">The vias are about 20um in diameter with an aspect ratio of about 10:1.</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">I would also consider Cu electroplating( after an appropriate ALD adhesion/base layer), but I’m not sure how feasible that is given the via diameter and aspect ratio.</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;"> </p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Thanks for your help!</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;"> </p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Larry</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;"> </p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Larry A. Hess, PhD</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">NASA</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Goddard Space Flight Center</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">8800 Greenbelt Road</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Code 553, Detector Systems Branch</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Building 11, Room E011</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">Greenbelt, MD 20771</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">301-286-0259 (P)</p>
<p style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;">301-286-1672 (F)</p>
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