<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
When we see that it often means you are overdue for chamber cleaning and reconditioning.</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
For us (SPTS Pegasus 150 mm tool) that is a long O2 chamber clean with a wafer on the chuck) followed by running our standard Bosch process on bare silicon full wafers until they come out shiny.</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
If that fails then you need manual chamber wall clean (is<span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">o and scotchbrite) followed by the above.</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">Best of luck,</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">Jim</span></div>
<div id="appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> labnetwork-bounces@mtl.mit.edu <labnetwork-bounces@mtl.mit.edu> on behalf of Pallavi Sharma <pnsharma@unm.edu><br>
<b>Sent:</b> Monday, July 27, 2020 10:02 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu <labnetwork@mtl.mit.edu><br>
<b>Subject:</b> [labnetwork] Deep Reactive Ion Etch Problems</font>
<div> </div>
</div>
<style type="text/css" style="display:none">
<!--
p
{margin-top:0;
margin-bottom:0}
-->
</style>
<div dir="ltr">
<div style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">
<span>Hello all,</span></div>
<div style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">
<span><br>
</span></div>
<div style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">
<span>I am having problem with anisotropic etching of silicon by Deep Reactive ion etch. Grass or black silicon is the issue all the time, attaching some of the SEM pictures of the sample. Every recipe I tried to fine tune result in grass formation, even as
the process initiates in tool wafer surface starts to turn brown and ultimately black. I tried varying SF6 gas flow, Bias power, Substrate temperature but every time I see is highly dense grass with no clean surface. </span></div>
<div style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">
<span>Any help will be greatly appreciated.</span></div>
<div style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">
<span><br>
</span></div>
<div style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">
<span>Thank you,<br>
Pallavi</span></div>
<div style="color:rgb(0,0,0); font-family:Calibri,Arial,Helvetica,sans-serif; font-size:12pt">
<span><br>
</span></div>
</div>
</body>
</html>