[labnetwork] question to cleanroom colleagues: distributed vs. manifolded gases...

[Daniel C. Christensen]

Another PRO for VMP's - when I need to replace an MFC in a tool, I am able to go to the VMP and evacuate AND PURGE the gas line for that particular tool while not disrupting the gas supply to the other tools. Replacing MFC's seems to occur more often in our case than adding and subtracting tools.

At Univ of Wisconsin we have VMP's and VMB's (hazardous gases). I would set the threshold for non-haz. gases to be >2 tools then use a VMP. For haz gases, I would use the VMB even for 2 tools. Certainly buy extra sticks in the VMP/B for future use. I am happy we spent the money to have them.

Dan C



On 09/20/12, Ian Harvey  wrote:
> 
> 
> 
> Dear micro/nano cleanroom colleagues:
> 
> Please critique the following thought process and give your insight which approach is best in planning the process gas piping for a new installation. 
> 
> 
> Which do you use (VMP/distributed) in your new facility or new tool installations and are you happy?
> 
> 
> If VMP's, what is the threshold number of tools for which you consider it justifiable to use VMP's?
> 
> 
> valve manifold panels:
> pro's: 
> • clean, organized installation, flexible to any future installation, populated when needed
> • system contamination attained by ability to purge regulators with venturi
> • leaks or failures within isolated runs do not contaminate other processes or cause downtime on other tools
> • prevent cross-talk between process MFC's, using the same gases
> • does not cause system downtime when installing new processes
> 
> 
> Con's
> • up front cost is greater, though not sure how much
> 
> 
> Process gases distributed through shared supply line, and laterals / drops:
> pro's:
> • Up front cost is lower (not sure how much-- it depends...)
> • cross-talk can be minimized by a regulator at each tool
> 
> 
> Con's:
> • system downtime for all tools sharing the gases during
> • cost may be comparable depending upon number of valved drops, and how good the planning is for predicting future installation points
> • see pro's above in VMP
> 
> 
> Thank you all!
> 
> 
> --Ian
> 
> 
> ********************************************
> Ian R. Harvey, Ph.D.
> Research Associate Professor
> Department of Mechanical Engineering
> Adjunct Associate Professor
> Department of Electrical & Computer Engineering
> 2511 SMBB (USTAR)
> 
> Associate Director,
> Utah Nanofab & 
> Micron Microscopy Core
> 
> 
> 801/585-6162 (voicemail)
> 801/581-5676 (lab main number)
> www.nanofab.utah.edu(http://www.nanofab.utah.edu)
> 
> mail to:
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--
Daniel C Christensen
Wisconsin Center for Applied Microelectronics
University of Wisconsin-Madison
dan at engr.wisc.edu 
608-262-6877