Hi Lando,

I am just wondering how can you do it with e beam evaporation. electron beam
beam can still react with PMMA and it can harden the polymer(PMMA acts as
negative tone resist under high dose)

It works well for me both RF sputtering and Thermal evaporation.

thanks,
sangeeth


On Wed, Jun 2, 2010 at 8:38 AM, landobasa  wrote:

> Dear Researcher,
>
> I am still a beginner in fabrication, and I have these following problems
> in the lift-off process. In order to provide the context, let me briefly
> write the process steps:
>
> 1) PMMA film (200nm thickness) is patterned using Electron  Beam
> Lithography (developed for 60s and IPA for 30s).
> 2) Patterned PMMA film was subjected to UV Ozone Stripper (SAMCO UV-1) for
> 60s.
> 3) The sample was deposited by Ti with 20nm thickness (with the rate of
> 0.06nm/s)
> 4) The sample was soaked in Acetone.
>
> Problems:
> 1) There are cracks everywhere in PMMA film after E-Beam Evaporation.
> 2) The PMMA cannot be removed by acetone.
>
> Any help would be very much appreciated.
>
> Best Regards,
>
> Lando

--
Sangeeth K
The Center of Excellence in Nanoelectronics
Indian institute of science
Bangalore-12