[labnetwork] Results of the STS RIE oxide etch mystery

[Morrison, Richard H., Jr.]

By our data that is what is happening, I do not understand at this time
if anything else plays a role. We also saw a reduction in N2 peaks
(using a plasma scope to look at the plasma cloud) and some other things
dropped. 

Good point about the patent, need to research that.

This Teflon ring makes the plasma harder to understand, if I get
anything I else I will share it with the group.

 

Rick

 

 

From: Bernard Alamariu [mailto:bernard at mtl.mit.edu] 
Sent: Thursday, August 11, 2011 2:04 PM
To: Morrison, Richard H., Jr.
Cc: labnetwork at mtl.mit.edu; Eric S. Lim; Bernard
Subject: Re: [labnetwork] Results of the STS RIE oxide etch mystery

 

Hi,

Great! 

I understood that you can sustain a 1,000A/ min  SiO2 etch with CFn+
ions from a Solid Teflon Source,
triggered by O2 plasma. Correct?

Very Interesting! Do you plan to make Patent application?

I think that would be a very good example of the just as they said:
"Don't let a Crisis go to Waste!"

Thanks, Bernard


On 8/10/11 3:57 PM, Morrison, Richard H., Jr. wrote: 

Hi Everyone,

 

I would like to thanks the many people that responded to my initial
email about the STS RIE tool etching SiO2 during an O2 plasma.

 

To sum up:

We replaced the vacuum pump to ensure no oil back streaming (Ebara dry
pump), no change in etch rate or in the plasma emission.

We replaced the cover o-ring (old one had Fomblin grease), no change in
etch rate or in the plasma emission.

Scrubbed the walls and ran long multi hour O2 clean, no change in etch
rate or in the plasma emission.

Removed the Teflon Shield Ring (installed around the chuck), etch rate
went to zero and F was gone from the plasma emissions.

 

So it appears that the O2 plasma is liberating F from the Teflon ring
which in turns etches the SiO2. We are consulting STS to see if there is
a fix. If there is I will let you all know.


Thanks

 

Rick

 

 

 

 

 

Rick Morrison

Senior Member Technical  Staff 

Acting Group Leader Mems Fabrication

Draper Laboratory

555 Technology Square

Cambridge, MA  02139

 

617-258-3420

 






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