Hi Shane,

   A layer of Ti would likely help the adhesion along with a brief sputter
etch of the Kapton.  In general polyimides can swell substantially in water
and for that reason have been used as elements in hygrometers.  In the past
we've had problems with metal delaminating from thin polyimide suspended
membranes upon contact with water requiring no exposure to aqueous
solutions after release.  In addition evaporation of SiO2 can produce thin
films with a great deal of residual stress that can lead to formation of
cracks and delamination.

Hope this helps,
Michael

On Mon, Nov 28, 2011 at 3:17 PM, Shane GUO  wrote:

> Hi,
>
> I should make a correction of my observation. It seems like the problem is
> the wetting of SiO2. Once the SiO2 was wetted, it lost adhesion with Kapton
> sheet. Any one met the similar problem? Was this caused by the method of
> depositing SiO2?
>
> Thank you