A Study on the Impact of Polymer Additives in Bulk Copper Slurry on Copper CMP

Polymer additives in bulk copper CMP slurries have been a crucial element in bulk copper CMP slurries; however, there are few studies in the literature which explore in detail the structure-function relationship between polymers and CMP performance. A key characteristic seems to lie in the fact that polymer additives cause the copper removal to follow non-Prestonian behavior. This, in turn, yields better planarization efficiency and thus a better final product. To offer some insight into this relationship, this study examined the impact that the physical and chemical properties of a series of carefully engineered polyacrylic acid derivatives have on the polishing performance of a standardized copper slurry formulation. The results of the investigation indicate that while molecular weight and polymer composition are important parameters, the polydispersity of the polymer is of lesser importance.