Tantalum and chromium adhesion to polyimide. Part 1. BPDA-PDA surface imidization and modification

BPDA-PDA (3,3',4,4'-biphenyl dianhydride-p-phenylenediamine) tetracarboxylic acid derived polyimide (PI) surface imidization is initiated at the 230-degrees-C cure step and reaches completion at the 300-degrees-C bake. Exposure of BPDA-PDA to CF4 reactive ion etching (RIE) results in a highly fluorinated surface, as expected. Ar sputter exposure of this highly fluorinated surface causes a significant reduction in the fluorine concentration and deposition of metal from the sample pallet. Scanning electron microscopy and atomic force microscopy analyses show that CF4 RIE treatment results in significant surface roughening of the polyimide, whereas Ar sputtering smoothens the virgin and the CF4 RIE exposed polyimide.