Dear Wei,

Did you try this deposition with a higher rate?

For example you can try 5A/sec.

I guess this will give you a better result. Otherwise i recommend increase your
deposition rate to 10A/sec.

Best Regards.

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> Date: Thu, 25 Feb 2010 16:28:08 -0800
> From: tangweipku@gmail.com
> To: mems-talk@memsnet.org
> Subject: [mems-talk] photoresist peeled off during Ni e-beam deposition
>
> 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