INVESTIGATION OF CMP DEFECTIVITY

Abstract

Owing to its higher conductivity and higher electromigration resistance, copper has been chosen to replace aluminum as interconnect material. Subsequently, coupled action of multilevel structure and dual damascene process that is employed to outline interconnects has signified the importance of chemical mechanical polishing (CMP) for achieving global planarization. While copper CMP appears to be a very promising technology, there remain several challenges to its implementation. This is further bewildered by the abundant factors and the interaction between these factors that will affect the overall performance of CMP process. This report will then address some of these issues by first understanding the general mechanism of copper CMP, followed by analyzing several defects generated during the process. Together with the literature study done, plausible root causes of the defects and solutions will be elucidated.