All PS-b-PDMS thin films were etched with a Plasmalab μEtch RIE using a two-step etch: The first step removed the surface wetting layer of PDMS on the BCP film by using a CF4 plasma (100 sccm), 100 mT, 50 W for 8 s. The second step, using an O2 plasma (100 sccm), 135 mT, 30 W for 60 s removed the PS and converted the PDMS block to SiOx.