Hi, Wei

the wafer annealing is a very hot "hard bake" (500°c for Pyrex 7740 i.e)
and it allow a very good organization for particles inside the wafer,
but the main cause of the stress is the difference in expansion between
your wafer and the deposited layer ( Ni), then to avoid the stress, it's
recommanded to deposit on the both side of your wafer.

I hope to be useful,


Alaa



Wei Tang a écrit :
> Hi, Alaa
>
> Thanks for the suggestions. I guess for my sample, the Ni film
> directly contact with the photoresist layer, and from the SEM picture
> shown in the link of my last post, the photoresist layer seems to be
> under big strain, and peeled off from the substrate (but still under
> the nickel layer). The wafer itself seems ok with nickel on it.
>
>  When referring to anneal the wafer, do you mean hard bake? I have
> tried hard bake at 130C before deposition, but the same problem
> remains. Could you specify a little bit more on wafer annealing?
>
> Thanks,
>
> Wei

--
Alaa el dine ALLOUCH
Doctorant au LAAS-CNRS-Groupe N2IS
7 Av colonel Roche, 31077 Toulouse
Tél : 05 61 33 78 71