Finite element analysis model was fabricated to confirm stress concentration phenomenon occurring in the wafer edge region in the CMP process, and it was confirmed if it corresponds to the measurement result of the actual pressure sensor. First, contact stress distribution at the edge of the wafer was calculated by the finite element analysis model in which material properties and boundary conditions were set up. As a result, an engineering contact stress distribution profile was obtained. Next, the pressure generated in the edge region of the wafer was measured using a pressure sensor that detects resistance change of the polymer. To compare with the result of the finite element analysis, the non-dimensional sensor signal unit was converted into the pressure unit, and correlation between the analysis and measurement results was obtained. As a result, the finite element analysis result, the actual pressure measurement, and the trend of the results were more than 90%. The results show that the finite element analysis model produced and modified in this study is consistent with the actual behavior trend of the components.

Chemical mechanical polishing achieves surface planarity through combined mechanical and chemical means. The role of the chemical reaction is very important in a metal CMP like aluminum. The slurry used in aluminum CMP typically consists of oxidizers, a chelating agent, corrosion inhibitors, and abrasives. This study investigates the effect of oxalic acid as a chelating agent for aluminum CMP with H2O2. To study the chemical effect of the chelating agent, the two methods of a polishing experiment and an electrochemical analysis were used. Lastly, it was confirmed that the optimum concentration of oxalic acid significantly improved the removal rate and surface roughness of aluminum.

The chemical mechanical planarization (CMP) process combines the chemical effect of slurry with the mechanical effect of abrasive (slurry)-wafer-pads The slurry delivery system has a notable effect on polishing results, because the slurry distribution is changed by the supply method. Thus, the investigation of slurry pumps and nozzles with regard to the slurry delivery system becomes important. This paper investigated the effect of a centrifugal slurry pump on a spray nozzle system in terms of uniform slurry supply under a rotating copper (Cu) wafer, based on experimental results and computational fluid dynamics (CFD). In conventional tools, the slurry is unevenly and discontinuously supplied to the pad, due to a pulsed flow caused by the peristaltic pump and distributed in a narrow area by the tube nozzle. Adopting the proposed slurry delivery system provides a higher uniformity and lowered shear stress than usual methods. Therefore, the newly developed slurry delivery system can improve the CMP performance.