In general, higher spin speeds and longer spin times create thinner films. The spinning speed is
one of the most important factors in spin coating process. As the resin dries, the viscosity increases until the radial force of the spin process can no longer move significantly the resin over the surface. At this point, the film thickness will not decrease significantly with an increased spinning time. The acceleration of the substrate towards the final spinning speed can also influence the coated film properties, since the resin begins to dry