<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thank you all for your input!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">We have decided to just plumb the process N2 with stainless all the way so there can be no objection to the material any longer. As for the purity of our process
nitrogen system from our tank, we will assume it is good enough for now not having an actual number but will plan on having an analysis done for future reference. I am sure this question will come up a year or two down the road and it would help to have some
backup documentation. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">If anyone knows of a company that comes on site that can test a few points on the system and provide analysis I would appreciate their contact info.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Best Regards!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Mark Heiden<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">NanoFab Cleanroom Manager<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Center for Nanoscale Science and Engineering<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">University of California, Riverside<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">951-827-2551<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<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"> Robert M. HAMILTON [mailto:bob@eecs.berkeley.edu]
<br>
<b>Sent:</b> Friday, July 31, 2015 9:02 AM<br>
<b>To:</b> Mark Heiden <mheiden@engr.ucr.edu><br>
<b>Cc:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> Re: [labnetwork] Nitrogen Purity for Sputtering<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">Mark Heiden,<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">The UC Berkeley Marvell NanoLab has looked into house, high-purityN2 versus UHP cylinder N2 in reactive sputter applications.Using a RGA we see more contamination with using cylinder N2 than our house-delivered N2. As per your note, the
NanoLab N2 is also derived from a cryogenic LN vessel. The spec from the LN vendor gives impurities of <1 ppm. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Having said this, N2 is delivery throughout the lab is branched to countless uses, including things like N2 blowoff guns. There is also significant use of plastic tubing and retractile hoses, all of which are subject to permeation. Partial-pressure
laws invariably mean the N2 delivery system is subject to back-diffusion. Long-ago we made sure that anytime a regulator goes into the N2 circuit, especially those cheap types, it is a non self-relieving type, yet another source for back-diffusion. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">As a sidebar to this conversation I question whether Teflon-PFA tubing and the associated fittings offer any advantage over polyethylene tubing when it comes to delivering N2 with high process purity.Teflon tubing and fittings are subject
to compression-set given time and like other polymers PTFE and extrudable variants have diffusion issues.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Given the above we decided that in processes where N2 becomes part of a critical thin film, we will add an N2 purifier cartridge. These typically come as a compact SS cartridge with face-seal (VCR) fittings and can be exposed to air, for
the short time required for installation. If you pick one of these make sure the reactive purifying material is a metal-alloy and not an organic. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">In system, gas sticks typically have a pneumatic isolation valve (Nupro) before and after a mass flow controller (mfc). The best place to install a purifier is in this circuit. Consider adding an additional valve to isolate the purifier
should an mfc needs change-out or have a VCR cap handy to protect it. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Given such placement the purifier cartridge will only see the actual amount of N2 requires by the process and otherwise remain isolated. Given good supply N2 purity it should last a long time - perhaps into retirements?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Regards,<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Bob Hamilton <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal"><br clear="all">
<o:p></o:p></p>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<p class="MsoNormal"><br>
Robert Hamilton<o:p></o:p></p>
</div>
<p class="MsoNormal">University of CA, Berkeley<br>
Marvell NanoLab Equipment Manager<o:p></o:p></p>
</div>
<p class="MsoNormal">Rm 520 Sutardja Dai Hall, MC 1754<o:p></o:p></p>
</div>
<p class="MsoNormal">Berkeley, CA 94720<o:p></o:p></p>
</div>
<p class="MsoNormal">Phone 510-809-8618 (desk - preferred)<o:p></o:p></p>
</div>
<p class="MsoNormal">Mobile 510-325-7557 (my personal mobile)<o:p></o:p></p>
</div>
<p class="MsoNormal">E-mail preferred: <a href="mailto:bob@eecs.berkeley.edu" target="_blank">
bob@eecs.berkeley.edu</a><br>
<a href="http://nanolab.berkeley.edu/" target="_blank">http://nanolab.berkeley.edu/</a><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">On Thu, Jul 30, 2015 at 3:12 PM, Mark Heiden <<a href="mailto:mheiden@engr.ucr.edu" target="_blank">mheiden@engr.ucr.edu</a>> wrote:<o:p></o:p></p>
<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in">
<div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">We are moving a sputtering system from a remote installation into our cleanroom and the intent has been to take it “off the bottle” and use the building process nitrogen system
for process gas as well as venting. The bottles on the old install were 99.999% but the building process nitrogen is not certified to any exact number. The piping comes out of the 9000 gal. tank and through a vaporizer, then it goes through filters then splits
into “house” nitrogen which is copper piping and “process” nitrogen which is all stainless steel with 10ra polished inside.
<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">From the stainless building process nitrogen line regulator, we ran high purity Teflon PFA tubing to the point of use filter on the MFC. Since I can’t provide a precise purity for
the evaporated nitrogen gas coming from the bulk tank and the tubing from the regulator to the filters is not stainless, a PI that was using the system is terrified that the nitrogen won’t be pure enough. Could I get your opinions on what the purity may be
expected to be and if it is less than 99.999% would the filters correct this anyway?
<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I’m sure most operations that spent the money for a “process” nitrogen system are not then running everything on bottles anyway so how do you ensure that the nitrogen being delivered
to the systems is pure enough?<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thanks in advance,<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Mark Heiden<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">NanoFab Cleanroom Manager<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Center for Nanoscale Science and Engineering<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">University of California, Riverside<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><a href="tel:951-827-2551" target="_blank">951-827-2551</a><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
</div>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
_______________________________________________<br>
labnetwork mailing list<br>
<a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
<a href="https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork" target="_blank">https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a><o:p></o:p></p>
</blockquote>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
</body>
</html>