I've seen such problems with SU-8 when it was near its expiration
date, so if you never experienced this problems before, but now its
suddenly occurring, it may be because the resist has degraded.

On Thu, Feb 11, 2010 at 6:47 PM, Paul Nguyen  wrote:
> Hello everyone,
>
> I haven't seen this phenomenon but last couple of days 2 incidents have made
> me wonder about the cause.  My wafer with 35um thick negative resist was
> peeled off as a sheet after develop.  Anyone has any ideas of the causes?
> More info: the wafer was SB with 2mins/67C and 8mins/125C, exp and PEB at
> 5mins/90C then develop; the wafer was cleaned and hydrophilic before
> coating. Resist is BPR100.
>
> Thanks in advance for any hints.
>
> Regards,
>
> Paul