Another method of polymer film formation involved spin coating the polyimide precursor varnish made of poly(pyromellitic dianhydride-co-4,4'-oxydianiline), amic acid solution 15.0-16.0 wt.% in N-methylpyrrolidone (NMP) (Pyre-M.L. RC-5019, Sigma-Ardrich). After spin coating on a Si substrate, the film was annealed at 200 • C for 4 hours in a vacuum chamber. A dehydration condensation between -NH and -OH was induced, resulting in PMDS-ODS polyimide formation. When an undiluted solution was spin coated on a Si substrate at 3000 rpm, a 3 µm thickness polyimide film was obtained. To optimize and lower the thickness to be suitable for MIM metasurface creation, solution was diluted with NMP. In this study, films of 45 nm and 335 nm thicknesses were made.