By a density functional method, the adhesion characteristics of polymer/Au with and without impurities are investigated. A slab model is employed to study the importance of different crystal faces. Results showed that in general the adhesion between the polymer and Au substrate is weak, regardless of any crystal faces. But the adhesion between polymer and Au(100) face is relatively stronger comparing with another two faces. Through geometry optimisation of polymer on Au(111), the effects of impurities including C, O, Si, NaOH and H2O are analysed. Results showed that the majority of the impurities are harmful for the adhesion, especially H2O and NaOH, which should be removed during wafer fabrication process. (C) 2003 Kluwer Academic Publishers.