Good question

Dear Thiyagarajan

I think this problem because mismatch between polymer and metal, therefore you must calculate mismatch between them.

good luck

I don't think that the thermal stress is a major problem, since film deposition on polymers needs to be done at low temperatures, to avoid thermal overloading of the polymer. We apply sputter deposition to grow molybdenum based thin films on PET (temperatures up to 100°C) without any adhesion problem. Which metal alloy do you want to deposit? What are the vacuum conditions used? Do you pre-treat the polymer before film deposition?

Dear Christian,

Bi-Sn alloy i want to deposit 10^-5 bar vacuum condition. Pre-treatment is not done but substrate temperature is maintained 80 degree Celsius.

I don't have any experience with Bi-Sn or its thermal vapor deposition. Probably, the kinetic energy of the film forming species is too low to activate the polymer surface, to promote adhesion. But if you can not use plasma discharges in your chamber, you can not affect that. Sorry...

An Ar-O2 plasma pretreatment of your substrates before the deposition would raise their surface energy. This should be at least helpful for a better adhesion

Thank you folks,

Continues trials gave good results. Optimizing substrate temperature and evaporation distance gives better results. I am also planning to upgrade my system to plasma assisted .