The phase behavior of dot-forming BCP thin films (such as PS-b-PDMS used in this work) is quite complex, as lamellae/wetting layers, single layer hexagonal or multiple stacked layers of hexagonal dots can be formed. Which phases form in a BCP thin film is strongly dependent on initial thickness, which needs to be commensurate with the native BCP pitch. Moreover, during SVA the film swells in thickness, often resulting in the formation of multiple layers. The final areal fraction of single layers (or desired phase) over the entire substrate is one of the most important (and often unreported) metrics of BCP thin film annealing. From the perspective of bit-patterned media devices, any regions that are not the desired phase would effectively consist of 100% defects.