PAG segregation during exposure affecting innate material roughness

Abstract

We have developed an improved AFM-based technique to measure intrinsic material roughness (IMR) after base development. We have investigated the contribution of different polymeric PAGs to IMR. These polymeric PAGs include copolymers of several styrenic PAGs with hydroxystyrene. The IMR of these polymer-bound PAGs is reduced relative to that of their nonpolymeric counterparts with DUV exposure. Theses results represent further evidence for PAG segregation during the bake steps as being responsible for increased IMR in exposed resists, presumably by increasing the dissolution rate inhomogeneity on a nano-scale level. The work also shows that the effects of PAG segregation can be mitigated by employing polymer-bound PAGs. 2