Hi all,
Like many of you, I was coating my Si wafer molds with a silanization agent (TFOCS) using vapor deposition technique to facilitate easy removal of PDMS.
However, the last time, I unfortunately added to much of TFOCS and coated my wafers with a really thick TFOCS layer which messed up the entire geometry.
Do you have any idea how can I remove TFOCS without damaging the wafer? I have poured PDMS and remove it multiple times but it seems like TFOCS layer remains intact. I tried to clean the wafer with IPA but it did not work either.
I appreciate any suggestions,
Thank you!
The problem will be selectively breaking the bonds of the silane without breaking the bonds in your structure (SU-8 I presume). The silane has formed a covalently bonded Si-O-Si network with the side chains being the functional group of the silane. This network is also covalently bonded to the native oxide on the wafer and any site that may have had hydroxyls exposed on the SU-8. You may be able to carefully plasma ash the silane and at least get a partially recovered structure but you'll have to watch out that you don't start to loose the corners of your structure. Good Luck!
Hi,
It happened a lot to me. You can try washing the wafer with isopropanol or acetone for a few minutes following by DI water rinsing. If you can put the wafer with acetone or isopropanol in an ultrasonic bath for 5 minutes, you can remove the most unbounded silane molecules.
I hope this works for you as well!
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