[labnetwork] Expired chemicals

[Miller, Timothy J]

Re: Hydrogen peroxide - it evolves O2, not H2. ;-)  The stabilized version usually has some sort of tin compound to slow the spontaneous breakdown, and has been shown to interfere with some processes.  We typically do not allow the stabilized version in our labs.

Tim Miller
Purdue University
Birck Nanotechnology Center
1205 West State Street
West Lafayette, IN 47907-2057


-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Morrison, Richard H., Jr.
Sent: Monday, July 16, 2012 6:28 AM
To: Matthieu Nannini, Dr.; labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Expired chemicals

Hi Matthieu,

In general solvent materials are ok to use after the expiration date, we leave it up to the engineer. Stuff like resist can be useable up to a year after they expire. The risk that you run is that you will need to change your exposure and development time. Then when you receive the new material the parameters will change again.

Hydrogen peroxide will not be active after the expiration date, the H2 comes out as a gas, that is why H2O2 has a vented cap. Be careful with H2O2 it comes in 2 flavors, stabilized and un-stabilized. The stabilized has an expiration date longer than the un-stabilized.

Other acids maybe ok to use after the date, but things like HF may change concentration over time as the gas evolves out of the solution.

Rick




-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Matthieu Nannini, Dr.
Sent: Thursday, July 12, 2012 2:53 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Expired chemcials

Dear colleagues,

What is your take on expired chemicals like:

- PMMA
- acids
- H2O2
- BOE
- TMAH
- LOR
- MIBK and solvents

Thanks

Matthieu

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