Thanks a lot! Your suggestions help.

I put more Cr as adhesion today and skipped the O2 plasma step.

Then I baked it on the hot plate @ 160 C and it was good. I tried to spin
PMMA and bake it in the oven @ 180 C for half an hour. Half part of the
pattern had the same issue and the other half was safe. It seemed to be
improved a lot~

As to your questions, there was no Cr left. I measured the thickness by
DECTAK profilometer. In the filament system, I used Chrome Plated Tungsten
Rods. Sometimes when I used up one rod and didn't realize it, the rod will
be broken.

All the best,
Jay

On Tue, Jun 17, 2008 at 11:45 AM, Rick Williston 
wrote:

> Jay
>
> Does it look like there is Cr left on what should be bare Si after
> delamination? That might be important. Also, how are you measuring thickness
> of the deposition? What kind of boat or crucible are you using for the
> metals in the hot filament system and how healthy are they? As you can see,
> I still have more questions than answers.
>
> Typically, an O2 plasma won't adversely oxidize silicon but it won't make
> up for inadequate development during lithography. If the plasma process
> isn't tuned properly or there are problems with the resist then it can
> transfer material from the resist to the open areas and not provide any
> substantial gains in cleaning. Lower power might be better if you're worried
> about this.
>
> It's not conclusive but the gold underneath the peeled films suggests it's
> not your litho process. If everything were fine with your metal layers and a
> resist residue were causing delamination then you'd expect Cr coloured
> underside. I'd guess off the top of my head that your Au layer is being
> overheated during deposition, perhaps due to too high a deposition rate or
> the source being too close to the target. The Au might be mixing with the
> underlying Cr, reducing it's usefulness as an adhesion layer and giving you
> some Au colouration on the underside. This is mere speculation not being
> able to see the films. I'd have thought that the temperature required for
> this would adversely affect the resist or make it difficult to remove
> though.
>
> Anyhow, I'd try a slower deposition for Au and it couldn't hurt as someone
> else pointed out to put down a thicker Cr adhesion layer.
>
> Good luck,
> Rick