Metallization process to obtain a microelectrode on a photopatternable polymeric substrate comprising the steps of depositing a material withlow adhesion, spin coating a negative photoresin A, Patterning its design,, protecting its uncured areas, depositing apositive photoresin B, and etch awaythem, Patterning the electrode using photolithography, metallizing the resulting surface, Etching away the positive photoresin polymers B and B', spin-coating a negative photoresin A and finally performing the final development, hence overcoming the state of the art difficulties providing a process for obtaining a photopatterned polymeric substrate microelectrode, with the ductility required to prevent the microelectrode from breaking and the thickness required to avoid folding during the insertion.