[labnetwork] KOH Tank Design

Tue Jul 23 06:14:28 EDT 2013

Hi,

I have used a reflux condenser (Lab Glass) with a heated jacket. I have never had the need for a stir bar with the heated jacket. For the condenser coil I use either cold water or a recir system to save on water going to the drain.
The web site for Lab Glass is  http://www.wilmad-labglass.com/ProductList.aspx?t=108

The beaker has a large flat on the top which is clamped to the cover. The cover has 3 holes, one for the condenser, one for a T/C and one extra, this works great for KOH and I also use it for EDP. The beaker fits into a heater jacket. This applies even heat to the solution so a stir bar is not needed.

Good luck.

Rick Morrison

Draper Laboratory
Group Leader Microfabrication Operations
555 Technology Square
Cambridge Ma, 02139-3563

www.draper.com
rmorrison at draper.com
W 617-258-3420
C 508-930-3461

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Tony L Olsen
Sent: Monday, July 22, 2013 6:03 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] KOH Tank Design

Dear Labnetwork

We are building a new wet bench and would like to include a dedicated KOH etch bath to replace the current methodology of glassware with stir bars on a hotplate.  We generally use a bath of 80°C.
Our wetbench vendor initially quoted a recirculated bath in a stainless steel tank.  We are concerned about the stainless, nor do we believe the Teflon or PVDF wetted surfaces in the proposed diaphragm pump will hold up to the hot KOH.  Another option we are aware of is a quartz tank heated externally by recirculated water.  I'm certain there are other options, too.
Can you share your experience with dedicated KOH baths?  What is the configuration?  What are the materials?  How do you mix/stir the bath?  What problems have you experienced?  What would you do next time?

Thank You,
tonyO

Tony Olsen
Nanofab Cleanroom Supervisor/Process Engineer
36 S Wasatch Dr, Suite 2500 SMBB
Salt Lake City,  UT  84112
801-587-0651 office
801-587-3077 fax
www.nanofab.utah.edu<http://www.nanofab.utah.edu/>

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