Adhesion property of Cu film on a low-k material was investigated. The low-k films deposited using a mixture of hexamethyldisilane(HMDS) and para-xylene had a dielectric constant as low as 2.7 and thermal stability up to 400°C. In this work, Ti glue layer, boron dopant, and N2 plasma treatment were applied to improve adhesion between Cu and the low-k films. Adhesion property was significantly enhanced by N2 plasma-treatment on the low-k film and boron dopant in Cu film. This enhanced adhesion was attributed to the formation of new binding states between Ti and the plasma-treated surface of the low-k film and to the diffusion of B from Cu to Ti and low-k films. Cu(B)/Ti/low-k film annealed at 350°C withstood an applied load of about 23 N during the scratch test.