Change in STS etch chiller temperature

Donald Disney ddisney at
Thu Mar 20 12:24:34 PST 2003


Good point.  The specific changes I observed in my process (that I assume
are related to the temperature change) are:

- Increase in photoresist undercut from about 0.80um to about 0.95um
- Change in sidewall angle from 90deg to 90.5deg (re-entrant)

These may not sound like large differences, but they are enough that I will
have to re-optimize my etch process for the new temperature.  Before I
invest in that effort, I'd like to see if there is support for restoring the
old temperature.

Thanks for your support.

Don Disney

-----Original Message-----
From: Nancy Latta [mailto:latta at]
Sent: Thursday, March 20, 2003 9:48 AM
To: Donald Disney
Cc: 'stsetch at'
Subject: Re: Change in STS etch chiller temperature


We are all for a survey of the users of stsetch, however, in your 
comments please include what you mean by degradation, changes or other 
strange observations.  Please be as specific as you can.  Just saying it 
has affected your etch does not help.



Donald Disney wrote:
> My etch results have also been degraded, apparently by the change in
> temperature.  I would like to see how many people were adversely impacted
> this change vs. the number that benefited.  I suspect more were adversely
> affected.  If so, I request that the SNF staff please consider reseting
> temperature.  Please send your comments.
> Don Disney
> -----Original Message-----
> From: Ben Jian [mailto:opticalmachine at]
> Sent: Thursday, March 13, 2003 3:29 PM
> To: stsetch at
> Subject: STS etch
> Dear STS Etch users,
> The chiller temperature on the STS Etch was recently changed from 13
> C to 20 C in response to users complaining about grass formation at 13 
> degree C, and will stay at 20 C for the foreseeable future. Unfortunately
> process is ruined by this temperate change. So with Nancy's approval, next

> Tuesday and Wednesday the chiller will be turned back to 13 C so that I
> get all my wafers etched. Sorry for any inconvenience this may cause.
> Best regards.
> Ben
> _________________________________________________________________
> MSN 8 with e-mail virus protection service: 2 months FREE*  

Nancy Latta
Stanford Nanofabrication Facility
CIS Room 145
420 Via Palou Mall
Stanford, CA 94305-4070
(650) 725-6727
latta at

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