Enhanced Performance of STI CMP by Pre-Irradiation Optimization of a Ce _{1– <i>x</i>} Y _<i>x</i> O ₂ /D-PVA-Based Slurry

With the continuous development of the semiconductor industry, shallow trench isolation (STI) technology is facing increasingly stringent performance requirements. Building on previous research on the dual-action mechanism of CeO₂/PVA abrasive particles, this study further optimized the performance of the abrasives through Y³⁺ doping modification. Combined with the results of ultraviolet spectroscopy analysis, photocatalytic degradation tests, and X-ray photoelectron spectroscopy (XPS) characterization, it was found that Ce_0.96Y_0.04O₂/D-PVA abrasive particles exhibit the best photocatalytic effect. Therefore, based on the Ce_0.96Y_0.04O₂/D-PVA system, the influence of pre-irradiation of the polishing slurry on the performance of STI CMP was further investigated. The study revealed that the polishing slurry pre-irradiated for 10 min achieved a SiO₂ removal rate of 2540.5 Å/min, which was 43.91% higher than that of the non-pre-irradiated group. The Si₃N₄ removal rate was 61.53% lower than that of the non-pre-irradiated group, and the selectivity ratio increased by 276.32% to 14.3. Meanwhile, the surface roughness of SiO₂ and Si₃N₄ was reduced to 0.139 and 0.128 nm, respectively, indicating a significant improvement in surface quality.