CHARACTERIZATION OF THE COMPOSITE CONDITIONING AIDED BY ULTRASONIC VIBRATION

摘要

As VLSI device chip has been rapidly developed, CMP has been accepted as one of the essential processes for VLSI fabrication. However, as the polishing process continues, pad pores get to be glazed by polishing residues. Moreover, pad surface is ununiformly deformed through radius for high pressure and velocity loaded on wafer. These defects make the decrease of removal rate with a number of polished wafer and the desired within-chip planarity, within wafer and wafer-to-wafer nonuniformity (WIWNU, WTWNU) are unable to be achieved. Because of these reasons, pad conditioning is very important process. The conventional diamond grit disk grinds the surface of the pad and makes new pore layer. But, this method has the defects like scratches on wafer out of diamond grits, subsidences of pad pores by over-conditioning. So, this paper focuses on cavitation effect induced by ultrasonic vibration to reopen glazed pores and brazed diamond wheel to remove ununiformly deformed pad away. Finally, the performance of composite conditioning, ultrasonic and brazed diamond conditioning, was verified with electroplated in Cu CMP and ILD CMP.