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在4H-SiC晶片的化学机械抛光(CMP)体系中加入紫外LED系统,研究TiO_2颗粒、紫外LED光功率、抛光温度和抛光液pH值对4H-SiC晶片抛光性能的影响规律,以获得较高的材料去除速率(MRR)和原子级光滑表面,满足LED器件对衬底材料表面的严格要求.结果表明,采用平均粒径25 nm、质量分数为2%的TiO_2颗粒,可显著提高MRR,且减少微划痕等表面缺陷;增大紫外LED功率,MRR随之增大;升高抛光温度,MRR快速提高,并可降低抛光所得表面粗糙度;在CMP体系中加入紫外体系可增加羟基自由基数量,抛光液pH值较低(2.2)也可维持较高MRR值,且抛光液pH值超过10时MRR值大幅提高.采用原子力显微镜(AFM)、光学显微镜来考察4H-SiC晶片抛光后的表面质量.基于各因素的影响规律,最终获得表面粗糙度为0.058 6 nm的4H-SiC晶片表面,且MRR达到352.8 nm/h.
The effects of TiO 2 particles, UV LED power, polishing temperature and polishing solution pH on the polishing performance of 4H-SiC wafers were investigated by adding a UV LED system to the chemical mechanical polishing (CMP) system of 4H-SiC wafers. (MRR) and atomically smooth surface to meet the stringent requirements of the LED device on the surface of the substrate material.The results show that the MRR can be significantly increased by using TiO 2 particles with an average particle diameter of 25 nm and a mass fraction of 2% Reduce the surface defects such as micro-scratches; increase the UV LED power, MRR increases; raise the polishing temperature, MRR rapid increase, and can reduce the surface roughness obtained by polishing; in the CMP system by adding UV system can increase hydroxyl radicals (2.2) also maintained a high MRR value, and the MRR value increased significantly when the pH value of the polishing solution was over 10. The atomic force microscope (AFM) and optical microscope were used to investigate the effect of 4H-SiC wafer after polishing Based on the influence of various factors, the surface of 4H-SiC wafer with surface roughness of 0.058 6 nm was finally obtained and the MRR was 352.8 nm / h.