X-ray emission study of ion beam mixed Cu/Al films on polyimide

Cu (40 nm)/Al/polyimide/Si was mixed with 80 keV Ar+ and N-2(+) from 5.0 x 10(15) to 15 x 10(15) ions/cm(2). Ultrasoft x-ray emission valence spectra (XES) of Cn; C, N and O excited by electron and photon radiation were used for study of chemical reactions in Cu/Al/PI/Si and PI/Si systems induced by ion beam mixing in dependence of type of ions and dose. It is found that i on beam mixing changes the chemical state of Cu atoms with respect to that of pure metal, These changes depend on the dose of ion beam bombardment and type of ions and are attributed to a formation of CuAl2O4 interfacial laye r, which can be responsible for enhanced interfacial adhesion strength. On the other hand, it is shown that the shape of C K alpha, N K alpha and O K alpha XES of ion beam mixed polyimide layer (PI/Si) is modified with ion bo mbardment. This means that the ion-beam mixing process is able to break the bonding of constituent atoms of irradiated PI layers and can induce the fo rmation of chemically bonded complexes linking atoms in the Cu,Al and PI la yers. (C) 1999 American Vacuum society. [S0734-2101(99)00202-X].