Hi,

Maybe you must deposit the Ni film on the both sides of your wafer?
This decreases a lot the stress.

You can also anneal your wafer before deposition.

Alaa


Wei Tang a écrit :
> Hi, all
>
> I have experienced a problem of photoresist peel off during the Nickel
> e-beam deposition (by CHA machine) process for lift-off purpose. The
> picture is shown:
>
> http://picasaweb.google.com/tangweipku/PRPeeledOffDuringEBeamDepositionOfNi#54
41568465466565330
>
>  I am guessing the problem comes from the residual stress in the as
> deposited Ni film.  The deposition rate is 3A/s and final thickness is
> 150nm. The PR is 1.4um AZ5214E and the pattern is made by
> image-reversal process. The SiO2 wafer have been primed in HMDS for
> 10min before spin coating.  I have tried several method below but NONE
> of them solve the problem:
>
> (1) hard bake at 130C for 5min after development (the undercut has
> been compromised a lot during the hard bake process)
>
> (2) UV bake for 35min
>
> I am wondering is there any way to overcome this problem by:
> (1) adjust the deposition parameter to produce less stress
> (2) treat the photoresist to increase the adhesion with the substrate
> (I have already primed the wafer with HMDS before coating)
>
> Any comments or suggestions are appreciated.
>
> Thanks,
>
> Wei
>
>


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