Self-assembly through phase separation in block copolymers (BCPs) thin films represents an attractive route to create spontaneously ordered patterns at the sublithographic range. The cost effectiveness, the fast parallel processing time as well as the compatibility with the standard microelectronics technologies make it among the most promising techniques to meet the ever challenging feature size requirements in nanotechnologies. In the present work, we investigate the behavior of cylinder forming poly (styrene-b-Methyl-Methacrylate) PS-b-PMMA self-assembly on a chemically neutralized 300 mm Silicon wafer. The effects of the process parameters such as the annealing temperature and time, the film thickness, and the BCPs periodicity on the holes formation after PMMA removal were studied in systematic fashion using statistical analysis of the Critical Dimension- Scanning Electron Microscope (CD-SEM) images,focusing mainly on the Critical Diameter (CD) and circularity of holes. In particular, it was found that both (CD) in the narrow range of 10–15 nm and a hole circularity of (0.8–0.9) in excess of 96% can be achieved on the whole wafer under appropriate processing conditions. The obtained results were correlated to the self-assembly process and shed some light on the dynamic of the phase separation process of BCPs. The level of reproducibility and control achieved on a 300 mm silicon wafer, hold a promise for future applications in nanotechnology.