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