I've also seen that standard polypropylene plastic wafer storage boxes can
outgas something that coats the wafers.

In contact-angle measurements on aluminum, a freshly cleaned surface had
zero contact angle.

After three days, the front wafer in the box had an increase in contact
angle to 35 deg, while the one behind it remained at zero contact angle.

    --Kirt Williams

----- Original Message -----
From: "Edward Sebesta" 
To: "'General MEMS discussion'" 
Sent: Thursday, January 15, 2009 5:39 PM
Subject: Re: [mems-talk] Lifting-Off 1um metal

>I can vouch for this. Plastic containers can be the source of many
> process problems from adhesion to corrosion due to outgassing. I have
> seen many cases over the years.
>
> Ed
>