ALERT: BOTTLE 2 OF THE 5% 495k PMMA SPINS OUT OF SPECIFICATION THICKNESS.
jwc at snf.stanford.edu
Fri Mar 9 16:32:28 PST 2007
Greetings 5% 495K PMMA Users ,
I just tried to spin some Si wafers with 5% 495K PMMA and had
difficulties pressing through a filter in a syringe and found the spin
thicknesses re much greater than specification. 1960 RPM should give
me about 300 nm and I am obtaining ~480 nm with very large variation
across one wafer and from wafer to wafer.
The material may have become gelled or hydrolysed from exposure to water
vapor, breaths, or other contaminations or it may be a odd batch from
I will look further into this Monday afternoon looking into this issue
more closely and track back to batch lots.
I recommend you spin up two wafers with the same spin speed and then
measure on nanospec and adjust your speed to obtain target resist
Users working with this material are requested to report their spin
speed thickness data to me by email to jwc at snf.stanford.edu
Thank you for your support!
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