<html 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;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style></head><body lang=EN-US link=blue vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Joseph, See: <a href="https://www.microchemicals.com/products/yellowlight_uv_filter.html">UV - Filter, yellow foil for Clean Room, Yellow Foil, Lithoprotect, MicroChemicals GmbH</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>However, my experience is to validate the filter efficiency by placing a coated wafer (half protected with aluminum foil) near the filtered lighted area for a number of hours and develop. If you see loss of film thickness within the exposed area than the filter is not adequately filtering the light at 300-400 nm.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheers,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Al Renaldo<o:p></o:p></p><p class=MsoNormal>Eng. Lab Manager<o:p></o:p></p><p class=MsoNormal>San Jose State University<o:p></o:p></p><p class=MsoNormal>San Jose, California</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sent from <a href="https://go.microsoft.com/fwlink/?LinkId=550986">Mail</a> for Windows</p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='border:none;padding:0in'><b>From: </b><a href="mailto:joseph.losby@ucalgary.ca">Joseph Losby</a><br><b>Sent: </b>Wednesday, February 22, 2023 1:33 PM<br><b>To: </b><a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br><b>Subject: </b>[labnetwork] Thoughts about sunlight entering cleanroom</p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal style='background:white'><span style='font-size:12.0pt;color:black'>Hello, in the planning of our new facility the architects have placed windows along a side of the cleanroom (which is fine). Outside of the windows is a hallway which is lined with large windows to the outside. This would allow for sunlight to pass through two sets of windows and into the cleanroom. Although standard windows are adequate for filtering a majority of shorter wavelength UV, some of the longer wavelength UV (UV-A, ~300-400 nm) will still transmit. It is of my belief that it's standard practice not to have sunlight entering the cleanroom (especially a litho area). <o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:12.0pt;color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:12.0pt;color:black'>Are any of your cleanrooms exposed to sunlight (I haven't seen any) and, if so, what type of window filtering do you use?<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:12.0pt;color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:12.0pt;color:black'>Cheers,<o:p></o:p></span></p></div><div><div><p class=MsoNormal><span style='font-size:12.0pt;color:black'><o:p> </o:p></span></p></div><div id=Signature><div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666'>Joseph Losby, PhD.</span><span style='font-size:12.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666'>Operations Manager, qLab</span><span style='color:black'><o:p></o:p></span></p></div></div></div></div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666'>Quantum City, University of Calgary</span><span style='font-size:12.0pt;color:black'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>