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<p>Hi Folks,</p>
<p><br>
</p>
<p>(RE: Mac's comments)</p>
<p><br>
</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. </p>
<p><br>
</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).<br>
</p>
<p><br>
</p>
<p>Your mileage may vary...electroplating is a dark art.<br>
</p>
<p><br>
</p>
<p>Best,</p>
<p>C<br>
</p>
<pre class="moz-signature" cols="72">--
Christopher Alpha
User Program Manager
Cornell Nanoscale Facility
Cornell University
250 Duffield Hall
343 Campus Rd
Ithaca, NY 14853
tel (607)254-4913
Any email from me will always really be from me without any AI "assistance"</pre>
<p></p>
<p> <br>
</p>
<div class="moz-cite-prefix">On 2/26/25 13:04, Hathaway, Malcolm R
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:DM6PR07MB6521681A2B9AC12263770898CBC22@DM6PR07MB6521.namprd07.prod.outlook.com">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style type="text/css" style="display:none;">P {margin-top:0;margin-bottom:0;}</style>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
Hi Larry,</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
As it happens, Cu is not an established ALD process yet (that I
am aware of).</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
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>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
Which is to say, ALD is slow. </div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
Typical films are under 200nm.</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
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>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
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>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
I'm happy to chat about this off-line if you like. Hopefully
others with proper electroplating experience will chime in
shortly.</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
Mac</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
Harvard CNS</div>
<div class="elementToProof"
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<div
style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
<hr style="display: inline-block; width: 98%;">
<div id="divRplyFwdMsg" dir="ltr"><span
style="font-family: Calibri, sans-serif; font-size: 11pt;"><b>From:</b> labnetwork
<a class="moz-txt-link-rfc2396E" href="mailto:labnetwork-bounces@mtl.mit.edu"><labnetwork-bounces@mtl.mit.edu></a> on behalf of Hess,
Larry A. (GSFC-5530) <a class="moz-txt-link-rfc2396E" 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 class="moz-txt-link-abbreviated" href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a>
<a class="moz-txt-link-rfc2396E" href="mailto:labnetwork@mtl.mit.edu"><labnetwork@mtl.mit.edu></a><br>
<b>Subject:</b> [labnetwork] Copper Through-Glass Vias on
fused silica</span>
<div> </div>
</div>
<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>
<p
style="margin: 0in; font-family: "Calibri", sans-serif; font-size: 11pt;"> </p>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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