The advantage of blend DSA (Directed Self Assembly) is milder anneal condition than PS-b-PMMA BCP
DSA materials and availability of conventional instruments. In this paper, blend type DSA was applied for
hole patterning. Target patterns were contact hole and oval hole. Polymer phase separation behavior has
been studied from the point of χN. In the case of polymer blend, χN needs to be more than 2 to give phase
separation. At first the effect of polymer size was studied. When the polymer weight was low, the shrunk
hole was not clean because of low χN. Furthermore, the correlation of shrink amount and χN was studied.
Higher χN polymer blend system gave higher shrink amount. High χN polymer systems give clear interface,
then the intermixing area would be reduced, then the attached polymer blend part became larger. The
polymer blend ratio effect was also investigated. The blend ratio was varied for polymer A/ polymer
B=70/30-50/50. The shrink amount of oval hole was reduced with increasing the ratio of polymer B.
However, the shrink amount ratio of CDY/CDX was almost constant (~3).