The final polishing of silicon results in the irresistible formation of micro-defects (i.e., particle residues and scratches) on the surface. In view of this problem, the synergistic effect of surfactants and water-soluble polymers in inhibiting the micro-defects on the silicon surface was studied to improve the wettability of the slurry and reduce the micro-flocculation of abrasive particles. The results showed that the total number of residual particles (≥0.06 µm) on the polished surface was reduced from 24,784 to 123 with the adsorption of cationic polyacrylamide (CPAM) and fatty alcohol polyoxyethylene ether (AEO-9). The water-soluble polyvinylpyrrolidone (PVP) polymer could coat on the SiO2 abrasives, inhibit the flocculation of abrasive particles, avoid scratches on the silicon surface and further reduce the number of residual particles (≥0.06 µm) to 67 on the polished surface. Furthermore, a contact angle analyzer was used to characterize the wettability of the components in the slurry, and a large particle counter was used to analyze the changes in the number of large particles in the slurry component. Finally, a mechanism of surfactants and a water-soluble polymer combined system was proposed to suppress the micro-defects on the surface of the silicon wafer.

The effects of silica abrasives of five different particle sizes (10 nm, 40 nm, 60 nm, 80 nm and 100 nm) on the removal rate of silicon wafers were studied. The experiments were performed under two conditions, by taking the abrasive particles of uniform size and of two different sizes. The mixture of abrasive particles of two sizes increased the removal rate of the silicon wafer, and this improvement was more apparent when 10 nm particles were mixed with any other particle size. According to the stability of the slurry, the size pair of 10 nm and 60 nm presented the optimal result for the particle size mixing of abrasives. The physical model of the abrasive distribution between the silicon wafer and the polishing pad was established. The mechanism of the effect of mixed abrasive on the increase of silicon wafer removal rate was presented. Further, the contact area between the abrasive and silicon wafer was calculated by MATLAB. Based on this, the removal rate of the silicon wafer by the abrasive with mixed-sized particles was predicted with an error value of less than 10%.

As the characteristic size of integrated circuits has continued to shrink, there has been increasing interest in using aluminum (Al) as the gate material. Here, we have looked at the role ethylenediamine tetraacetic acid dipotassium (EDTA-2K) plays in the chemical mechanical polishing (CMP) of Al for use as a gate material. Currently, the preferred approach to CMP is to use colloidal silica as an abrasive, EDTA-2K as the complexing agent, and H2O2 as the oxidant. We have explored the influence of EDTA-2K and H2O2 on the Al removal rate (RR) during CMP. The results show that when the concentration of EDTA-2K is 1 wt%, the removal rate reaches 3450 Å/min, and the surface roughness is 0.425 nm. The mechanism of the action of EDTA-2K during CMP was studied through particle size distribution analysis, X-ray photoelectron spectroscopy, electrochemical tests, and UV-visible spectroscopy. The results show that EDTA-2K reacts with aluminum ions (Al3+) to form a soluble Al-EDTA complex, which promotes the corrosion rate on the Al surface and thus increases the removal rate of Al.