[labnetwork] ALD venting precautions

[Tim Gilheart]

Hi Zuzanna,

We have implemented essentially the same solution Mac describes here, and find the pre-pump filter does extend pump operational life.

One modification: we have our exhaust routed through a dry scrubber in the new cleanroom here at Rice, which is may not be entirely necessary, but we had a convenient point of connection and capacity to spare. It actually saved us having to run an additional non-scrubbed exhaust header.

The exhaust systems are much better than Rice's old facility that I’m sure you remember all too well.

Best of luck,

-- 
Tim Gilheart, Ph.D.
Research Scientist - Nanofabrication Cleanroom Manager,
Shared Equipment Authority (SEA), Rice University
Cell: 832-341-5488 | Office: 713-348-3159 | gilheart at rice.edu

> On Mar 28, 2020, at 9:08 AM, Hathaway, Malcolm R <hathaway at cns.fas.harvard.edu> wrote:
> 
> Hi Zuzanna,
> 
> We vent our exhaust from our fomblin-base pump into our general exhaust (not sure at the moment if it's the solvent or acid-gas exhaust, we're shut down at the moment). 
> 
> The volumes of process gas involved are miniscule if your recipe are set up correctly, so that very little abatement is necessary, compared to what one expects for a CVD system.
> 
> What many manufacturers are doing these days (an easy retrofit, as well) is to place a mist filter just prior to the pump, which provides a large surface for "wetting out" of any excess precursor, thus allowing this precursor to react into oxide (generally) before entering the pump.  This reduces the volume of reactive gases still further, and keeps your pump happy for a longer period.  The reaction products coat the filter element, which gets cleaned or changed out every few years.
> 
> Do you plan to install a commercial system, or a home-made one?
> 
> Mac Hathaway
> Senior Process and Systems Engineer
> Harvard CNS
> From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> on behalf of Zuzanna A. Lewicka <zlewicka at princeton.edu>
> Sent: Friday, March 27, 2020 5:47 PM
> To: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
> Subject: [labnetwork] ALD venting precautions
>  
> Dear Labnetwork Community,
>  
> We are trying to get more information about appropriate venting precautions (e.g. proper exhaust abatement system or just heated ALD trap) for Thermal Atomic Layer Deposition System configured for alumina, hafnia and titania on Si, GaAs, and InP substrates. We would appreciate if you could share your experiences and solutions at your facilities.
>  
> Thank you,
> Zuzanna Lewicka
>  
> Senior Research Specialist
> Princeton Institute for the Science and Technology of Materials (PRISM) Cleanroom
> Email: zlewicka at princeton.edu <https://urldefense.proofpoint.com/v2/url?u=https-3A__owa.princeton.edu_owa_redir.aspx-3FC-3D-5Fobjl9mq7yUMTgAiqvOi4fXDy7oF3uDvC7guzRPqpQi1k7GZDK-5FVCA..-26URL-3Dmailto-253azlewicka-2540princeton.edu&d=DwMFAg&c=WO-RGvefibhHBZq3fL85hQ&r=TEMLD8-VsxCGtcVzmvpT5GFNSczskEKHzW6aYlttmIY&m=H2eHOHgwCSx5yx4sT24izIBIbxGKsmMOVUcp73oX52w&s=BguTXvbuS_Wr5MDvs33YNFVxFo7buP3du3f2BySz0-k&e=>
>  
>  
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