James,

I have used SPR220-7 (~9µm)  to etch through 10µm of GaAs/AlGaAs laser
structure using a BCl3 mixture in an ICP etcher.  Selectivity wasn't
great, about 1.5:1 and I was left with under 3µm of resist after
etch.  It was a reliable process.  I don't have any information on the
AZ resists, but there's one data point for you.

Brad Cantos
brad.cantos@holage.com
http://holage.com

LinkedIn: http://www.linkedin.com/in/bradcantos


On Feb 11, 2009, at 3:13 AM, James Paul Grant wrote:

> Hello all,
>
> Apologies for a vague question here but here it is anyway: What
> photoresist is more resistant to dry etching - AZ4562 or SPR220-7?
>
> I realize my question is far too simplistic as the selectivity will
> depend on process gases, powers, pressures, resit processing (hard
> bake etc.)........
>
> Does anyone have any experience of the two photoresists?
>
> Many thanks,
>
> Dr. James Paul Grant