Characteristics of High Rotational Speed Polishing with Oscillation Speed Control
The miniaturization of semiconductor devices is advancing rapidly. The requirement for wafer flatness is becoming increasingly stringent as the use of shorter wavelengths in the latest laser lithography results in a smaller focusing depth of field. In our research, a flatness of 0.1 µm has been achieved over an entire 12" wafer surface by planarization with oscillation speed control type polishing. However, in addition it is necessary to increase the removal rate in order to reduce the polishing time. Although high rotational speed polishing is a solution to meet this requirement, the polishing characteristics change with the rotational conditions. Using a simulation program, we calculated that the stock removal saturates as the rotational speeds of the wafer and polishing pad are increased beyond a certain point. Also, experimental results showed that at high rotational speeds actual stock removal is significantly less than that indicated by the simulation, and that too much slurry causes unnecessary etching.
Yury M. Baron, Jun'ichi Tamaki and Tsunemoto Kuriyagawa
K. Yoshitomi et al., "Characteristics of High Rotational Speed Polishing with Oscillation Speed Control", Key Engineering Materials, Vols. 291-292, pp. 355-358, 2005