[labnetwork] LiF in evaporation systems

[Aaron Hryciw]

Dear colleagues,

We have recently received a request from one of our users to deposit
lithium fluoride in our e-beam evaporation system, for OLED applications.
This is a non-loadlocked, cryopumped, multi-user system housed outside our
cleanroom in our "10k area", typically used to deposit common metals and a
few relatively innocuous dielectrics.  The large bell jar is periodically
cleaned by one of our staff members using power tools (i.e., particle
generation), while wearing a respirator.

After reviewing MSDSs (two are attached), we've got some concerns about the
toxicity of this materials, including the possibility of HF formation (with
the potential to be released during a cryopump regen?), as well as the
general exposure of this material to staff (and users in the surrounding
area) during cleaning.  Especially given the multi-user nature of this
tool, I am hesitant to allow LiF in it.

I would welcome any advice you have regarding whether or not to allow
deposition of this material, especially any other safety concerns and
special control measures you may recommend.

We are also considering the possibility of depositing LiF using a
high-temperature
thermal evaporation source
<http://luxel.com/products/thermal-evaporation-equipment/radak-and-oled-furnaces/>
in our organics evaporator.  As a smaller, more dedicated OLED system, it
may be possible to use a disposable foil liner, etc., to mitigate exposure
to toxic materials and simplify their disposal.

Cheers,

 – Aaron





Aaron Hryciw, PhD, PEng

Fabrication Group Manager

University of Alberta - nanoFAB

W1-060 ECERF Building

9107 - 116 Street

Edmonton, Alberta

Canada T6G 2V4 Ph: 780-940-7938
www.nanofab.ualberta.ca
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