Adhesion properties of copper/polyimide film modified by reactive ion etching(RIE)

Abstract

Surface modification of polyimide(PI) films was treated with oxygen RIE by varying ion doses from 1x10(16) to 1x10(18) ions/cm(2) at an ion beam energy of 250 eV. Following the modification of PI surface, metal films consisting of NiCr/Cu and Cu were deposited on modified PI films by D.C. magnetron sputtering and electroplating, respectively. The surface modified PI film was characterized by XPS, AFM, SEM and contact angle measurement, respectively. The water contact angle of PI film decreased significantly from 64 degrees to 4.4 degrees with an increase of ion dose, indicating that the surface energy of PI film increased. The XPS spectrum showed that functional group, particularly C-O bonding, on modified PI surface was significantly increased by interaction between scissored unstable chains and reactive ions. The modified PI film surfaces by oxygen RIE showed significant improvement in adhesion to a overcoated metal film of NiCr/Cu.