We have monitored the evolution of the structure of multilayered-granular films deposited by alternately growing thin cobalt layers and thicker copper layers by RF-sputtering. In particular, we have observed how the reduction of the Co layer thickness affects the overall structure of the samples and the morphology of the magnetic particles. Synchrotron radiation has been used to do diffraction, reffectivity and small angle scattering measurements, performed in anomalous configuration, in order to increase the low Co-Cu electron density contrast. We find that the samples are made of large columnar grains whose size depends on Co nominal thickness. A good agreement between the results of the X-ray analysis and the magnetic properties of the samples has been found.