Tantalum adhesion on SiLK (TM) was investigated using first-principles method based on density functional theory. Phenylene groups were found to play a major role and the adjacent semi-benzene rings also contribute significantly to Ta adhesion on SiLK (TM). In addition, the degradation effects of H-2/He reactive plasma clean on Ta adhesion on SiLK (TM) was investigated. Based on our findings, argon plasma treatment was suggested and implemented after reactive plasma cleaning process, which resulted in integration of SiLK (TM) with Cu up to seven metal layers. (c) 2005 American Institute of Physics.