[labnetwork] Expired chemicals

[Morrison, Richard H., Jr.]

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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