<html class="apple-mail-supports-explicit-dark-mode">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body dir="auto">
Dear Filippo,
<div><br>
</div>
<div>I have over forty years of experience in sputtering thin films of all kinds. Here are my answers to your questions.</div>
<div><br>
</div>
<div>1. Cross-contamination between adjacent targets is not a problem at all since dark space shields are used. We have sputtered more than forty layers of up to seven different materials in the same chamber, with no cross-contamination, and sharp interfaces
of atomic layer thicknesses.</div>
<div><br>
</div>
<div>2. If the photoresist is hard-baked you should be fine with sputtering on it at ambient temperatures. </div>
<div><br>
</div>
<div>3. We have used Kapton tape extensively in our UHV sputtering chamber at temperatures up to 500 degrees C with no problems at all.</div>
<div><br>
</div>
<div>Please don’t hesitate to contact me if you have any questions about sputtering. </div>
<div><br>
</div>
<div>Best regards,</div>
<div>Su</div>
<div><br>
</div>
<div>Subhadra Gupta, PhD</div>
<div>Fellow, American Vacuum Society</div>
<div>Professor Emerita</div>
<div>Metallurgical and Materials Engineering </div>
<div>Former Director </div>
<div>Micro-Fabrication Facility </div>
<div>University of Alabama</div>
<div>https://sites.ua.edu/sgupta<br id="lineBreakAtBeginningOfSignature">
<div dir="ltr"><br>
</div>
<div dir="ltr"><br>
<blockquote type="cite">On Aug 11, 2026, at 1:47 PM, Gary Riggott <riggottg@mit.edu> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<table border="0" cellspacing="0" cellpadding="0" width="100%" style=" aspect-ratio: revert !important; background: revert !important; block-size: revert !important; border: revert !important; bottom: revert !important; color: revert !important; color-scheme: revert !important; content-visibility: revert !important; cursor: revert !important; direction: revert !important; display: revert !important; font-size: revert !important; height: revert !important; hyphens: revert !important; letter-spacing: revert !important; line-height: revert !important; margin: revert !important; opacity: revert !important; order: revert !important; outline: revert !important; overflow: revert !important; padding: revert !important; position: revert !important; resize: revert !important; rotate: revert !important; scale: revert !important; tab-size: revert !important; table-layout: revert !important; text-align: revert !important; text-indent: revert !important; text-orientation: revert !important; text-overflow: revert !important; text-shadow: revert !important; text-transform: revert !important; text-wrap: revert !important; top: revert !important; transition: revert !important; user-select: revert !important; vertical-align: revert !important; visibility: revert !important; white-space: revert !important; width: revert !important; word-break: revert !important; word-spacing: revert !important; writing-mode: revert !important; zoom: revert !important; cellpadding: 0 !important; border: 0 !important; cellspacing: 0 !important; display: table !important; width: 100% !important; table-layout: fixed !important; border-collapse: seperate !important; float: none !important; border-spacing: 0px 0px !important; " align="left">
<tbody style=" aspect-ratio: revert !important; background: revert !important; block-size: revert !important; border: revert !important; bottom: revert !important; color: revert !important; color-scheme: revert !important; content-visibility: revert !important; cursor: revert !important; direction: revert !important; display: revert !important; font-size: revert !important; height: revert !important; hyphens: revert !important; letter-spacing: revert !important; line-height: revert !important; margin: revert !important; opacity: revert !important; order: revert !important; outline: revert !important; overflow: revert !important; padding: revert !important; position: revert !important; resize: revert !important; rotate: revert !important; scale: revert !important; tab-size: revert !important; table-layout: revert !important; text-align: revert !important; text-indent: revert !important; text-orientation: revert !important; text-overflow: revert !important; text-shadow: revert !important; text-transform: revert !important; text-wrap: revert !important; top: revert !important; transition: revert !important; user-select: revert !important; vertical-align: revert !important; visibility: revert !important; white-space: revert !important; width: revert !important; word-break: revert !important; word-spacing: revert !important; writing-mode: revert !important; zoom: revert !important; display: block !important; ">
<tr style=" aspect-ratio: revert !important; background: revert !important; block-size: revert !important; border: revert !important; bottom: revert !important; color: revert !important; color-scheme: revert !important; content-visibility: revert !important; cursor: revert !important; direction: revert !important; display: revert !important; font-size: revert !important; height: revert !important; hyphens: revert !important; letter-spacing: revert !important; line-height: revert !important; margin: revert !important; opacity: revert !important; order: revert !important; outline: revert !important; overflow: revert !important; padding: revert !important; position: revert !important; resize: revert !important; rotate: revert !important; scale: revert !important; tab-size: revert !important; table-layout: revert !important; text-align: revert !important; text-indent: revert !important; text-orientation: revert !important; text-overflow: revert !important; text-shadow: revert !important; text-transform: revert !important; text-wrap: revert !important; top: revert !important; transition: revert !important; user-select: revert !important; vertical-align: revert !important; visibility: revert !important; white-space: revert !important; width: revert !important; word-break: revert !important; word-spacing: revert !important; writing-mode: revert !important; zoom: revert !important; ">
<td valign="middle" width="1px" bgcolor="#A6A6A6" cellpadding="7px 2px 7px 2px" style=" aspect-ratio: revert !important; background: revert !important; block-size: revert !important; border: revert !important; bottom: revert !important; color: revert !important; color-scheme: revert !important; content-visibility: revert !important; cursor: revert !important; direction: revert !important; display: revert !important; font-size: revert !important; height: revert !important; hyphens: revert !important; letter-spacing: revert !important; line-height: revert !important; margin: revert !important; opacity: revert !important; order: revert !important; outline: revert !important; overflow: revert !important; padding: revert !important; position: revert !important; resize: revert !important; rotate: revert !important; scale: revert !important; tab-size: revert !important; table-layout: revert !important; text-align: revert !important; text-indent: revert !important; text-orientation: revert !important; text-overflow: revert !important; text-shadow: revert !important; text-transform: revert !important; text-wrap: revert !important; top: revert !important; transition: revert !important; user-select: revert !important; vertical-align: revert !important; visibility: revert !important; white-space: revert !important; width: revert !important; word-break: revert !important; word-spacing: revert !important; writing-mode: revert !important; zoom: revert !important; padding: 7px 2px 7px 2px !important; background-color: #A6A6A6 !important; valign: middle !important; width: 0px !important; ">
</td>
<td valign="middle" width="100%" bgcolor="#EAEAEA" cellpadding="7px 5px 7px 15px" color="#212121" style=" aspect-ratio: revert !important; background: revert !important; block-size: revert !important; border: revert !important; bottom: revert !important; color: revert !important; color-scheme: revert !important; content-visibility: revert !important; cursor: revert !important; direction: revert !important; display: revert !important; font-size: revert !important; height: revert !important; hyphens: revert !important; letter-spacing: revert !important; line-height: revert !important; margin: revert !important; opacity: revert !important; order: revert !important; outline: revert !important; overflow: revert !important; padding: revert !important; position: revert !important; resize: revert !important; rotate: revert !important; scale: revert !important; tab-size: revert !important; table-layout: revert !important; text-align: revert !important; text-indent: revert !important; text-orientation: revert !important; text-overflow: revert !important; text-shadow: revert !important; text-transform: revert !important; text-wrap: revert !important; top: revert !important; transition: revert !important; user-select: revert !important; vertical-align: revert !important; visibility: revert !important; white-space: revert !important; width: revert !important; word-break: revert !important; word-spacing: revert !important; writing-mode: revert !important; zoom: revert !important; width: 100% !important; background-color: #EAEAEA !important; padding: 7px 5px 7px 15px !important; font-family: wf_segoe-ui_normal, Segoe UI, Segoe WP, Tahoma, Arial, sans-serif !important; font-size: 12px !important; font-weight: normal !important; color: #212121 !important; text-align: left !important; word-wrap: break-word !important; ">
<div style=" aspect-ratio: revert !important; background: revert !important; block-size: revert !important; border: revert !important; bottom: revert !important; color: revert !important; color-scheme: revert !important; content-visibility: revert !important; cursor: revert !important; direction: revert !important; display: revert !important; font-size: revert !important; height: revert !important; hyphens: revert !important; letter-spacing: revert !important; line-height: revert !important; margin: revert !important; opacity: revert !important; order: revert !important; outline: revert !important; overflow: revert !important; padding: revert !important; position: revert !important; resize: revert !important; rotate: revert !important; scale: revert !important; tab-size: revert !important; table-layout: revert !important; text-align: revert !important; text-indent: revert !important; text-orientation: revert !important; text-overflow: revert !important; text-shadow: revert !important; text-transform: revert !important; text-wrap: revert !important; top: revert !important; transition: revert !important; user-select: revert !important; vertical-align: revert !important; visibility: revert !important; white-space: revert !important; width: revert !important; word-break: revert !important; word-spacing: revert !important; writing-mode: revert !important; zoom: revert !important; ">
You don't often get email from riggottg@mit.edu. <a href="https://aka.ms/LearnAboutSenderIdentification" style="background: revert !important;color: revert !important;content-visibility: revert !important;direction: revert !important;display: revert !important;font-size: revert !important;opacity: revert !important;rotate: revert !important;scale: revert !important;visibility: revert !important;">
Learn why this is important</a> </div>
</td>
<td valign="middle" align="left" width="75px" bgcolor="#EAEAEA" cellpadding="7px 5px 7px 5px" color="#212121" style=" aspect-ratio: revert !important; background: revert !important; block-size: revert !important; border: revert !important; bottom: revert !important; color: revert !important; color-scheme: revert !important; content-visibility: revert !important; cursor: revert !important; direction: revert !important; display: revert !important; font-size: revert !important; height: revert !important; hyphens: revert !important; letter-spacing: revert !important; line-height: revert !important; margin: revert !important; opacity: revert !important; order: revert !important; outline: revert !important; overflow: revert !important; padding: revert !important; position: revert !important; resize: revert !important; rotate: revert !important; scale: revert !important; tab-size: revert !important; table-layout: revert !important; text-align: revert !important; text-indent: revert !important; text-orientation: revert !important; text-overflow: revert !important; text-shadow: revert !important; text-transform: revert !important; text-wrap: revert !important; top: revert !important; transition: revert !important; user-select: revert !important; vertical-align: revert !important; visibility: revert !important; white-space: revert !important; width: revert !important; word-break: revert !important; word-spacing: revert !important; writing-mode: revert !important; zoom: revert !important; width: 75px !important; background-color: #EAEAEA !important; padding: 7px 5px 7px 5px !important; font-family: wf_segoe-ui_normal, Segoe UI, Segoe WP, Tahoma, Arial, sans-serif !important; font-size: 12px !important; font-weight: normal !important; color: #212121 !important; text-align: left !important; word-wrap: break-word !important; align: left !important; ">
</td>
</tr>
</tbody>
</table>
<div>Hi Filippo-<br>
<br>
We have 2 Aja Orion systems here. One is for 4 inch wafers and wafer pieces, the other can accommodate 6" wafers and pieces.<br>
<br>
We manage these tools differently. The 4 inch tool has fewer restrictions, meaning that we allow resists for lift off processes and Kapton tape to secure samples. In the other tool, we don't allow either of these.<br>
<br>
1- I'm not sure what to say about cross-sputtering. You can minimize this by using gun positions that are widely spaced, as opposed to being adjacent or near each other. One thing to be aware of is the vapor pressure of the materials that you deposit. For
example, sulfur containing compounds tend to have high vapor pressures. Once this is in your chamber, it may be hard to reach your original chamber base pressure.<br>
<br>
For chamber and parts cleaning, we have a grit blaster that uses glass beads to remove deposits.<br>
<br>
Lab users have much higher rates of success with lift off processes done in our evaporators, but many still use the sputter tools.<br>
<br>
2- We allow a wide range of resists, like LOR 10A. In the photo of our tool, you may notice an RGA. We generally don't see any peaks beyond O2 at 32 amu. Photos may not transmit thru Labnetwork.<br>
<br>
3- We are OK with Kapton in one of our tools. The adhesives are silicone based adhesives, and I can't find outgassing data on these adhesives no matter whom I ask or where I look.<br>
<br>
Hope this helps,<br>
Gary
<pre class="moz-signature" cols="72">Gary Riggott
508-451-0905</pre>
<br>
<div class="moz-cite-prefix">On 8/10/2026 10:13 PM, #MARTINELLI FILIPPO# wrote:<br>
</div>
<blockquote type="cite" cite="mid:PUZPR01MB516505E7E232F97CC2E7889FEADD2@PUZPR01MB5165.apcprd01.prod.exchangelabs.com">
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
Dear labnetwork community,</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
I have recently been put in charge of a UHV magnetron sputtering system (AJA Orion) that I need to maintain and operate. The machine is dedicated to co-sputtering of two metals in a nitrogen environment.</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
The previous operator strongly advised me to be careful about what goes into the chamber, as contamination can affect both the chamber condition and the properties of the deposited material. However, she was not very specific about what exactly causes contamination,
and I am unsure how restrictive I should be with the materials I load.</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
I have a few questions I would appreciate your opinion on:</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
1. I read that cross-sputtering can occur between nearby substrates, or between the substrate and the chamber. In your opinion, are there materials that are particularly prone to cross-sputtering and hard to remove with standard cleaning routines, and that
should therefore be avoided in the chamber altogether?</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
2. Following on from that, what is your take on lithography resists?</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
3. How about mounting materials such as Kapton tape or Crystalbond?</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
I am quite new to this, so any suggestion or recommendation is welcome. I look forward to hearing your opinions.</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
Cheers,</div>
<div style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);">
Filippo</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
<pre wrap="" class="moz-quote-pre">_______________________________________________
labnetwork mailing list
<a class="moz-txt-link-abbreviated" href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a>
<a class="moz-txt-link-freetext" href="https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork" originalsrc="https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork">https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a>
</pre>
</blockquote>
<br>
</div>
<div><20260811_105744.jpg></div>
<span>_______________________________________________</span><br>
<span>labnetwork mailing list</span><br>
<span>labnetwork@mtl.mit.edu</span><br>
<span>https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork</span><br>
</div>
</blockquote>
</div>
</body>
</html>