novak,

we have successfully used BPR100 photoresist with
cyanide based plating baths. Also dry film photoresist
would be a good alternative (sth like DuPont
GoldMaster photoresist) and it is quite compatible
with cyanide based baths as well.

Regards,
Adnan Merhaba

--- Novak Farrington 
wrote:

> Hi all,
>
> could anyone recommend a combination of thick
> photoresist (~65um but thinner
> would be OK as I could use a multilayer application)
> and commercial gold
> electroplating bath which work well together? The
> electroplated gold needs to
> be around 50um for a 'bump' type process on a GaAs
> substrate.
>
> I've had experience in the past with a cyanide based
> bath (puramet 402) but this
> seemed to be incompatable with most common resists,
> showing the usual documented
> problems.
>
> For this reason I'm open to using either sulfite or
> cyanide based electrolytes.
> I was thinking about using BPR 100 (possibly with
> thinner) or a multilayer
> AZ45xx/AZ92xx resist.
>
> >From some of the publications I've seen, the
> sulfite electrolytes exhibit a
> rather high pH (up to 9.5) which is rather worrying
> - from experience, to what
> degree does this affect the photoresist?
>