Jongho,
       Early adhesion methods for Polymide used AminoPropylTriEthoxySilane,
APTES.  It worked so well the Polymide manufacturers incorporated it into the
liquid Polymide.  The old method of using it was to mix it with water and spray
or spin it on.  I have a vapor deposition system that puts sown vapor APTES and
other silanes.  If it is practical I can put down a vapor APTES coating for you.
Bill Moffat