Dear Aamer Mahmood The cracks might be due to the
stress developed in the polyimide substrate inorder to
remove it try heating the substrate to the same temp
as you would like to heat the sub and the coating with
out a Sio2 layer and then reduce the temp and then you
can deposit the Sio2 layer this will improve the
adhesion and temp stress developed in the film when
heat curing.

Thanks
Sarfaraz Moh





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