长余辉发光粒子与光催化剂在SiC晶圆化学机械抛光中的协同作用

目的 获得一种可改善单晶SiC晶圆化学机械抛光(CMP)效率的复合增效技术,实现单晶SiC晶圆高效率和低成本的加工要求,并对其增效机理进行深入研究。方法 通过抛光实验和原子力显微镜测试,探究长余辉发光粒子(LPPs)与不同光催化剂的协同作用对SiC–CMP的材料去除速率和表面粗糙度的影响。结合扫描电子显微镜(SEM)、紫外–可见漫反射光谱仪(UV–vis)、光致发光光谱仪(PL)和X射线光电子能谱仪(XPS)等仪器的测试结果,研究LPPs与光催化剂的协同增效机理。结果 与传统CMP的条件相比,在光催化条件下采用LPPs(质量分数0.5%)+TiO2(质量分数0.5%)+ H2O2(质量分数1.5%)+Al2O3(质量分数2%)的抛光液时,SiC的材料去除速率(MRR)由294 nm/h提高到605 nm/h,同时获得的晶圆表面粗糙度(Ra)为0.477 nm。然而,采用含有LPPs和ZrO2的抛光液抛光SiC时,其材料去除速率和表面粗糙度都未得到明显改善。XPS测试结果表明,LPPs与光催化剂的协同作用增强了抛光液对SiC的氧化作用。UV–vis和PL测试结果显示,LPPs与不同光催化剂协同效果的差异主要与其光学性能有关。结论 在光催化条件下,LPPs和TiO2对单晶SiC–CMP具有协同增效的作用,然而LPPs和ZrO2没有展现出协同增效的作用,即LPPs与光催化剂的协同作用可以改善SiC–CMP的性能,但是光催化剂的选择需要考虑LPPs的发光特性。

Synergistic Effect of Long-afterglow Phosphor Particles and Photocatalyst in Chemical Mechanical Polishing of SiC Wafers

The work aims to obtain a composite synergistic technology that can improve the efficiency of chemical mechanical polishing (CMP) of single crystal SiC wafers to meet the high-efficiency and low-cost processing requirements of single crystal SiC wafers and conduct in-depth research on its synergistic effect. The effects of the synergistic effect of LPPs and different photocatalysts on the material removal rate and surface roughness of SiC-CMP were studied through polishing experiments and atomic force microscope tests. Combined with scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, photoluminescence spectroscopy and X-ray photoelectron spectroscopy, the synergistic mechanism of LPPs and photocatalysts was explored. Compared with traditional CMP conditions, when the polishing slurry "0.5wt.% LPPs + 0.5wt.% TiO2 + 1.5wt.% H2O2 + 2wt.% Al2O3 Ra) of the wafer decreased to 0.477 nm. However, when polishing SiC substrates with polishing slurry containing LPPs and ZrO2, neither MRR nor Ra was significantly improved. XPS tests showed that the synergistic effect of LPPs and photocatalyst enhanced the oxidation effect of polishing solution on SiC substrates. UV-vis and PL tests showed that the variability of the synergistic effect of LPPs and different photocatalysts was mainly related to their optical properties. Under photocatalysis, LPPs and TiO2 have a synergistic effect on the performance of SiC-CMP; however, LPPs and ZrO2 does not show a synergistic effect. That is, the synergistic effect of LPPs and photocatalysts can improve the performance of SiC-CMP, but the choice of photocatalyst needs to be considered in conjunction with the luminescence characteristics of LPPs.