Hi,

I am trying to make micro strain gauges using the following method in
summary:

- Spin 250nm-thick polyimide diluted with NMP; completely cure at 325C
- Sputter/pattern 80nm-thick Cu/Ni on cured polyimide
- Spin 250nm-thick polyimide diluted with NMP; completely cure at 325C

The problem I am having is that after the cure, the polyimide above Cu/Ni
layer is disappearing.  I read about copper oxide diffusion into polyimide
due to the reaction between copper and polyamic acid; but I am not sure if
this explains the material loss over the metal lines.

I already tried amino silane adhesion promoters provided by GE Silicone, but
didn't have any success.

I would be grateful if somebody could suggest a solution.

Thank you very much.

erkin