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<span style="margin:0px;font-size:12pt;background-color:rgb(255, 255, 255)"><span style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif">Hello Everyone,</span></span>
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<div style="margin:0px;font-size:12pt;background-color:rgb(255, 255, 255)"><span class="x_gmail_default" style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255, 255, 255)">During nitride/oxide deposition with <span style="margin:0px;background-color:rgb(255, 255, 255);display:inline !important"><b>Unaxis-750
PECVD</b></span>, we are getting a mirror image of shower head on the wafer, i.e., spots. We cleaned the chamber with CF4 for 2 consecutive days, each day 4:30 hrs. The conditions were </span>
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<span style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;color:rgb(0, 0, 0)">CF4 = 100 sccm, Temp = 250 C, chamber pressure = 600 mT, time = 4:30 hrs </span></div>
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<span style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;color:rgb(0, 0, 0)">We also evacuated the silane gas line, but there is no leakage.</span></div>
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<span class="x_gmail_default" style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255, 255, 255)">After completing the cleaning, when we conditioned the chamber and deposited nitride, the spots were lightened. But
on the second day, the spots look enlarging again.</span><br>
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<div style="margin:0px;font-size:12pt;background-color:rgb(255, 255, 255)"><span class="x_gmail_default" style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255, 255, 255)">Can anyone please suggest solution to this
issue? </span></div>
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<div style="margin:0px;font-size:12pt;background-color:rgb(255, 255, 255)"><span class="x_gmail_default" style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255, 255, 255)">Thanks,</span></div>
<div style="margin:0px;font-size:12pt;background-color:rgb(255, 255, 255)"><span class="x_gmail_default" style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255, 255, 255)">-Vibhor Kumar-</span></div>
<div style="margin:0px;font-size:12pt;background-color:rgb(255, 255, 255)"><span class="x_gmail_default" style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255, 255, 255)">Postdoctoral Associate</span></div>
<div style="margin:0px;font-size:12pt;background-color:rgb(255, 255, 255)"><span class="x_gmail_default" style="margin:0px;font-size:11pt;font-family:Arial, Helvetica, sans-serif;background-color:rgb(255, 255, 255)">Rutgers, The State University of New Jersey. </span></div>
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