Try 3 H2SO4: 1 H2O2: 1 H2O at 80 oC.

--- Ferda Mravenec  writes:

> Hello all,
>
> I am solving a problem with masking of the
> boro-silicate and soda-lime glass samples. I need a
> Ti mask on the glass with straight lines without Ti
> layer. The straight lines are from 1 to 3 um (widths
> of the mask opening ). One chance is make Lift off
> procedure but I think it could be done by simpler
> way.
>
>  I would like to make 100-200 nm Ti layer on the
> glass surface (i.e. BK7...), than I coat a
> photoresist (i.e. SU8), develop and do anisotropic
> etching of the titanium layer. I have found some
> solutions like H2O2, HF, KOH which are suitable for
> Ti layer etching but HF is dangerous and also I
> afraid about undercutting and glass surface damage.
> Does anyone know some suitable recipe for this work?
>
> Thanks a lot for any suggestion.
>
> Ferda Mravenec