Metallization process to obtain a microelectrode on a photopatternable polymeric substrate comprising the steps of depositing a material with low adhesion, spin coating a negative photoresin A, Patterning its design, protecting its uncured areas, depositing a positive photoresin B, and etch away them, 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.