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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Aptos",serif">For the electroplating of vias with Pt seed, have you seen poor nucleation, basically large grain growth vs uniform small grain size bottom up fill?
<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> labnetwork <labnetwork-bounces@mtl.mit.edu>
<b>On Behalf Of </b>Christopher Alpha<br>
<b>Sent:</b> Thursday, February 27, 2025 10:41 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> Re: [labnetwork] Copper Through-Glass Vias on fused silica<o:p></o:p></span></p>
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<span style="font-family:"Verdana",sans-serif;color:#212121">This message was sent from outside of HRL. Please do not click links or open attachments unless you recognize the sender and know that the content is safe.</span><o:p></o:p></p>
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<pre><span style="color:black"><br> </span><o:p></o:p></pre>
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<p>Hi Folks,<o:p></o:p></p>
<p><o:p> </o:p></p>
<p>(RE: Mac's comments)<o:p></o:p></p>
<p><o:p> </o:p></p>
<p>We often do Pt seed layers by ALD for via Cu electroplating fills...you can get voids though depending on aspect ratio and how you drive the plating. If a a hollow wire is OK this is fine to do in this fashion. <o:p></o:p></p>
<p><o:p> </o:p></p>
<p>If you want a full solid fill we have done Au or Pt sputter on only one side of a very high aspect ratio via and basically try to sputter the hole mostly if not fully closed and use a plating fixture that makes contact on the back side with the Pt seed,
leaving the other side exposed in the plating bath, then you can get a nice fill by plating from the bottom of the via up. Overtop the via/wafer's surface, and CMP everything clean and flat (remove seed either selectively with wet chemistry if possible or
CMP that off too).<o:p></o:p></p>
<p><o:p> </o:p></p>
<p>Your mileage may vary...electroplating is a dark art.<o:p></o:p></p>
<p><o:p> </o:p></p>
<p>Best,<o:p></o:p></p>
<p>C<o:p></o:p></p>
<pre>-- <o:p></o:p></pre>
<pre>Christopher Alpha<o:p></o:p></pre>
<pre>User Program Manager<o:p></o:p></pre>
<pre>Cornell Nanoscale Facility<o:p></o:p></pre>
<pre>Cornell University<o:p></o:p></pre>
<pre>250 Duffield Hall<o:p></o:p></pre>
<pre>343 Campus Rd<o:p></o:p></pre>
<pre>Ithaca, NY 14853<o:p></o:p></pre>
<pre>tel (607)254-4913<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>Any email from me will always really be from me without any AI "assistance"<o:p></o:p></pre>
<p> <o:p></o:p></p>
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<p class="MsoNormal">On 2/26/25 13:04, Hathaway, Malcolm R wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">Hi Larry,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">As it happens, Cu is not an established ALD process yet (that I am aware of).<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">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!<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">Which is to say, ALD is slow. <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">Typical films are under 200nm.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">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.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">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.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">I'm happy to chat about this off-line if you like. Hopefully others with proper electroplating experience will chime in shortly.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">Mac<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif">Harvard CNS<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Aptos",serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> labnetwork
<a href="mailto:labnetwork-bounces@mtl.mit.edu"><labnetwork-bounces@mtl.mit.edu></a> on behalf of Hess, Larry A. (GSFC-5530)
<a href="mailto:larry.hess-1@nasa.gov"><larry.hess-1@nasa.gov></a><br>
<b>Sent:</b> Wednesday, February 26, 2025 9:36 AM<br>
<b>To:</b> <a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a> <a href="mailto:labnetwork@mtl.mit.edu">
<labnetwork@mtl.mit.edu></a><br>
<b>Subject:</b> [labnetwork] Copper Through-Glass Vias on fused silica</span> <o:p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hi,<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">I am looking for a (hopefully established) source to deposit ALD copper on Though-Glass Vias.<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">The vias are about 20um in diameter with an aspect ratio of about 10:1.<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">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.<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Thanks for your help!<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Larry<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Larry A. Hess, PhD<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">NASA<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Goddard Space Flight Center<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">8800 Greenbelt Road<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Code 553, Detector Systems Branch<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Building 11, Room E011<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Greenbelt, MD 20771<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">301-286-0259 (P)<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">301-286-1672 (F)<o:p></o:p></span></p>
<p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<o:p></o:p></p>
<pre>_______________________________________________<o:p></o:p></pre>
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