HDMS treatment of SU8 mold used for PDMS thin film fabrication
Andrew
2009-08-17
Hi Bill,
How do you deposit the heptadecafluoride? I am looking for a surface that
remains hydrophobic after patterning. For example: deposit SiO2,
functionalise SiO2 to remain hydrophobic, pattern and etch SiO2 +
hydrophobic layer and remove mask. The surface must remain hydrophobic
after processing.
Thanks,
Andrew
2009/8/13 Bill Moffat
> There are better chemical than HMDS and TCMS. For release agents you
> are looking for the highest achievable water contact angle. Teflon has
> 13 fluorine molecules facing out and a contact angle of 120 degrees.
> With a heptadecafluoride there are 17 fluorine molecules facing out and
> a contact angle of 130 degrees. Good news but the real secret is to
> totally dehydrate before the chemical sees the mold. If it sees
> moisture it reacts with the moisture but breaks free later when it sees
> moist room air. This gives erratic surface tension modification. How
> big are your molds? Bill