Slurry Study Of Copper CMP

Cu Chemical-Mechanical Polish (CMP) is one of the fastest-growing processes in the semiconductor manufacturing industry. Today CMP can achieve global surface planarization of the various thin film layers that constitute the integrated circuit. Despite the rapid increase in CMP applications, there still are many problems associated with CMP process, particularly the understanding of the wafer-slurry-pad interactions that occur during the CMP process. New applications of CMP are expected to expand to materials that are complex chemically and fragile mechanically. Fundamental understanding and improvement of slurry design for CMP is the key to the development of next-generation CMP process.Slurry performance for CMP can be determined by several output parameters including removal rate, global planarity and surface defect. To achieve global planarity, it is essential to form a very thin passivation surface layer that is subsequently removed by the mechanical component of the slurry or by combined chemo-mechanical effects. Chemical additives like hydrogen peroxide (H2O2), are added to slurries as oxidizers in order to form a desirable surface layer. Other chemical additives such as inhibitors and complexing agents are added to the copper slurry in order to modify the oxide layer. In this study, various complexing agents and inhibitors are combined to form slurry chemistry for copper CMP processing in H2O2 based slurries at pH values ranging from 2 to 10. Two complexing agents and one inhibitor were selected as slurry constituents for detailed chemical synergistic effect study because they showed good materials removal and surface planarity performances. Use this kind of slurry do the experiment to evaluate the defect and take improve actions.To understand the fundamental mechanisms involved in copper CMP process with the afore-mentioned slurry chemical formations, various techniques, such as, x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM), were applied. As a result, the guidelines for optimized slurry chemical formulation were gotten and the possible mechanisms of surface-chemical-abrasive interactions were determined.