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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hi Deon,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">I found the UV filters photobleached with time and became less effective.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">After my initial inquiry a few years ago, my end solution was to go with a native amber LED. This is as opposed to more typical phosphor-converted LED, which uses a
<u>blue</u> LED to excite a phosphor that emits orange. I didn’t want to deal with the “maybes” and “what-ifs” of having white/blue light anywhere in the system. With a native amber LED, I can know with absolute certainty that lab members’ resist woes are
not due to the lights.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">These native amber fixtures were semi-custom, at least in my form factor, but several vendors were willing to quote the work. We ended up paying $38k for 140 fixtures, which
included spares in case a few die over the next 20 years. I realize that’s more expensive, but so are failed processes! Averaged over 20 years, it’s only $2k/y. Not bad.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Fab techs/engineers complained for a day or two about the lighting being “more orange,” similar to folks in Ana’s lab, but they quickly got used it and forgot that there was
a color difference from the old lights (white LEDs with filters). We’ve been very happy with the result.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Best,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Travis<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-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"> Collins, Deon <deonc69@illinois.edu>
<br>
<b>Sent:</b> Wednesday, March 4, 2026 2:16 PM<br>
<b>To:</b> Cohen, Ana N CTR USARMY DEVCOM ARL (USA) <ana.n.cohen.ctr@army.mil>; labnetwork@mtl.mit.edu; Massey, Travis <massey21@llnl.gov><br>
<b>Subject:</b> Re: Re: [labnetwork] Light filtering in photolithography bays<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="color:black">Revisiting this older post.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black">HMNTL has T-8's currently with UV filters. <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black">Before I pull the trigger on filtered LED replacements, I want to make an inquiry. I am contemplating purchasing nonfiltered LEDs and reusing the UV filters from our CFL bulbs. Being we have 8 photolithography
labs; initial conservative savings look to be around $5000.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black">Superbrightleds T8BDA-30K18A-30PK at 568.50 for a 30 pack <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">Vs Superbrightleds T8U4-SW5C22-F-25PK at 199.99 for a 25 pack<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black">Thanks in advance. <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="elementtoproof"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#002060">Deon D. Collins</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="elementtoproof"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#002060"> </span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="elementtoproof"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#002060"><br>
<i>Director of Facilities</i></span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="elementtoproof"><i><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#002060">The Grainger College Of Engineering UIUC</span></i><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#002060"><br>
Holonyak Micro & Nanotechnology Lab</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><br>
</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#13294B">208 N Wright St Rm. 1114 | MC-249</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><br>
</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#13294B">Urbana, IL 61801</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><br>
</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#13294B">217-300-7531 |
</span><u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0563C1"><a href="mailto:deonc69@illinois.edu"><span style="color:#0563C1">deonc69@illinois.edu</span></a></span></u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><br>
<br>
<br>
</span><a href="https://urldefense.us/v3/__http:/illinois.edu/__;!!G2kpM7uM-TzIFchu!248iO78McTq49lWLpgFtmXickcg8iXevKK83UTDVii_LuGwhySm-zcgYhVTdUgSb8BhPOaR5CpAYu0PZVDhqSw$"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;text-decoration:none"><img border="0" width="118" height="20" style="width:1.2291in;height:.2083in" id="Picture_x0020_1" src="cid:image001.png@01DCABFF.687E2560"></span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><br>
<br>
</span><i><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#666666">Under the Illinois Freedom of Information Act any written communication to or from university employees regarding university business is a public record and may be subject
to public disclosure. </span></i><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="elementtoproof"><u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span></u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="elementtoproof"><b><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#A3238B">Life begins at the end of your comfort zone.
</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="elementtoproof"><b><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#A3238B"> Propeck Amanda</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="elementtoproof"><span style="font-size:11.0pt;font-family:"Calibri",sans-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;color:black">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"> labnetwork <<a href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>>
on behalf of Cohen, Ana N CTR USARMY DEVCOM ARL (USA) <<a href="mailto:ana.n.cohen.ctr@army.mil">ana.n.cohen.ctr@army.mil</a>><br>
<b>Sent:</b> Friday, February 17, 2023 9:55 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>>;
<a href="mailto:massey21@llnl.gov">massey21@llnl.gov</a> <<a href="mailto:massey21@llnl.gov">massey21@llnl.gov</a>><br>
<b>Subject:</b> Re: [labnetwork] Light filtering in photolithography bays</span> <o:p>
</o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:11.0pt">Hi Travis,<br>
<br>
A couple years ago we switched our lithography bay fluorescents (T8) to<br>
amber tube LEDS from Super Bright LEDs. The light is more orange than yellow<br>
so took a little adjusting (many users first thought it was darker than<br>
usual), but visibility has actually been much better since we these bulbs<br>
are more stable and we don't end up with dark patches from dead<br>
fluorescents.<br>
<a href="https://urldefense.us/v3/__https:/www.superbrightleds.com/t8-uv-blocking-led-tube-clean-room-18w-1800-__;!!G2kpM7uM-TzIFchu!248iO78McTq49lWLpgFtmXickcg8iXevKK83UTDVii_LuGwhySm-zcgYhVTdUgSb8BhPOaR5CpAYu0MVbCEHIA$">https://www.superbrightleds.com/t8-uv-blocking-led-tube-clean-room-18w-1800-</a><br>
lumens-single-end-dual-end-ballast-bypass-type-b-32w-equivalent-1800k+packam<br>
t-30-Pack <br>
<br>
Our fume hoods are still fluorescent bulbs with filters. I've definitely<br>
noticed a degredation over time, but our facilities also have purchased<br>
different filters over the years, so I can't provide much comparison to your<br>
situation. However, it may be that your LEDS are emitting higher wavelengths<br>
than the fluorescents. UV Process has UV filters along with the color tubes<br>
which could be useful<br>
<a href="https://urldefense.us/v3/__https:/www.uvprocess.com/c3/1790-gamtube-and-supertube-filters.html__;!!G2kpM7uM-TzIFchu!248iO78McTq49lWLpgFtmXickcg8iXevKK83UTDVii_LuGwhySm-zcgYhVTdUgSb8BhPOaR5CpAYu0OKBX3hFQ$">https://www.uvprocess.com/c3/1790-gamtube-and-supertube-filters.html</a><br>
<br>
We don't filter our computer screens because don't notice much light<br>
pollution and we don't keep anything photosensitive nearby long-term, but<br>
you can definitely turn down the brightness and blue saturation on the<br>
monitors. We also have not needed to replace the darker pigment filters on<br>
our doors' windows, but similar to the monitors they are placed sufficiently<br>
distant from the photoresists/coated substrates.<br>
<br>
Good luck!<br>
Ana<br>
<br>
--<br>
Ana N. Cohen [she/her/hers]<br>
Photolithography Cleanroom Technician<br>
Contractor | General Technical Services, LLC<br>
US Army Research Laboratory<br>
2800 Powder Mill Road, Adelphi, MD 20783<br>
Tel: 301-394-1527<br>
Email: <a href="mailto:ana.n.cohen.ctr@army.mil">ana.n.cohen.ctr@army.mil</a><o:p></o:p></span></p>
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