The 'zone-model' for sputter deposited Cu films was analyzed by positron annihilation spectroscopy to give a valuable insight in the nature of the defects present in the different zones of the model. Both depth selective Doppler broadening and positron lifetime spectroscopy were applied using slow positron beams. Room temperature grain growth for films sputtered in the zone-T regime was also analyzed for the first time with positron annihilation spectroscopy.