Regarding Michael's point below, that cracking in SU-8 is due to
over-exposure:

While intuitively this makes sense, in practice it's not what I've seen. In
my experience, a wide exposure matrix, starting well below the optimal dose,
always shows obvious, macroscopic cracking when *under*exposed. These
disappear entirely when overexposed, even when highly overexposed (though of
course, eventually your features eventually disappear as well...)

Anyone else care to weigh in on this?

- Kevin

On 2/19/08 11:43 PM, "Michael Larsson"  wrote:

> Hi Sonic,
>
> The cracking indicates your layer is under high tensile stress. I would
> guess that the through-thickness cracking is the combined effect of
> over-exposure and/or over-baking (i.e. excess dehydration).


*********************************
Kevin Paul Nichols
MESA+ Institute for Nanotechnology
Mesoscale Chemical Systems
Meander 151
University of Twente
Postbus 217
7500 AE Enschede
The Netherlands

Office: +31 (0)53 489 26 31
Mobile: +31 (0)6 49 312 471
Fax   : +31 (0)53 489 35 95
Email : k.p.nichols@utwente.nl