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?

Thanks in advance to all users,

Novak