[labnetwork] [ICP-RIE] low temperature pseudo-Bosch process

[Ethan Morse]

Hi Gloria,

 

I recently completed an undergraduate thesis on developing a cryogenic DRIE process using SF6 + O2 at -100 °C chamber temperature on an Oxford Plasmalab 100 ICP-RIE. I achieved aspect ratios up to 18:1 for a 20:00 min etch, meaning it would likely be >20:1 if I increased the etch time.

 

Because my test samples were <4 in., I had to use a thermal grease between the 4 in. carrier wafer and my test sample. This has potential for chamber contamination, but is easily controlled by careful preparation. Otherwise, the process seems quite safe for the chamber and user.

 

Attached is my thesis for you to read through, along with relevant cryogenic DRIE literature. Feel free to contact me if you have any questions.

 

Ethan Morse

Texas A&M AggieFab Nanofabrication Facility

ethan.morse97 at gmail.com

 

From: Larry Rehn <larry.rehn at att.net>
Date: Monday, April 6, 2020 at 16:24
To: Ethan Morse <ethan.morse97 at gmail.com>
Subject: Fw: [labnetwork] [ICP-RIE] low temperature pseudo-Bosch process

 

Hey Ethan,

 

Do you want to share your experience (and maybe report) for the benefit of the university lab network?  See question below from Sydney, Australia, using Oxford RIE tool.

 

Larry

 

----- Forwarded Message -----

From: Gloria Qiu <gloria.qiu at sydney.edu.au>

To: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>

Sent: Sunday, April 5, 2020, 06:36:38 PM CDT

Subject: [labnetwork] [ICP-RIE] low temperature pseudo-Bosch process

 

Dear all,

 

We have received requests to run the pseudo-Bosch (SF6+C4F8) process at -5C to -50C on Oxford ICP-RIE 100s and I am very concerned because:
Oxford suggests to run it at >5C since condensation might affect pumping speed;
The C4F8 in the process might condense on the sample in low temperature;
As I understand the cryogenic Si etch uses SF6+O2, not the C4F8.
I am wondering if you have any experience running this process in low temperatures, below zero degree in particular.

 

Any comment is appreciated.

 

Thank you & stay safe.

 

 

 

Best,

 

Gloria

 

Wenlan (Gloria) Qiu

Senior Process Engineer | Research & Prototype Foundry

Core Research Facilities | Research Portfolio

 

THE UNIVERSITY OF SYDNEY
Level 4, Sydney Nanoscience Hub A31 | The University of Sydney | NSW | 2006

M +61 452 493328 
E gloria.qiu at sydney.edu.au  | W Research and Prototype Foundry

 

 

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