In order to fabricate SERS-active substrates suitable for sensing applications, reproducibility and efficiency issues must be tackled. Innovative nanofabrication techniques allow the preparation of substrates reproducible and easy to model. Theoretical modelling provides a very powerful method for optimizing the design of such substrates, i.e. tailoring their geometrical parameters for optimizing the optical response. In particular in this work a 1D digital metallic grating has been theoretically investigated to identify the configuration corresponding to the localization of the near-field radiation inside the slits. This chip has been fabricated by electron beam lithography (EBL) and electrolytic growth. The Raman enhancement factor of the chip has been measured and compared with the theoretical estimation.