摘要
目的提高6H-SiC晶片Si面化学机械抛光(CMP)的材料去除率(MRR),改善其抛光表面质量。方法使用含有不同Cu^(2+)浓度和甘氨酸形成的配合物作为催化剂、H2O2作为氧化剂的抛光液,对6H-SiC晶片Si面进行CMP。使用精密天平称量SiC晶片抛光前后的质量,计算其MRR。使用AFM观测Si C晶圆表面,测其表面粗糙度(Ra)。使用Zeta电位仪测量在不同Cu^(2+)浓度下纳米氧化硅磨粒的Zeta电势和粒径分布。使用摩擦磨损试验机测量不同Cu^(2+)浓度时Si C晶圆的摩擦系数。对比不同压力和转速在CMP中对Si C的MRR和Ra的影响。结果随着Cu^(2+)浓度的增大,MRR先增大后减小,在Cu^(2+)体积浓度为300μmol/L时,MRR有最大值,为82 nm/h,此时,Ra为0.156 nm;相比之下,不加入Cu^(2+)-甘氨酸配合物的MRR为62 nm/h,Ra为0.280 nm。同时,随着Cu^(2+)浓度的增大,一方面,溶液中磨粒的Zeta电势绝对值不断减小,但高于不加入Cu^(2+)-甘氨酸配合物时的Zeta电势绝对值;另一方面,其平均粒径逐渐增大,但低于不加入Cu^(2+)-甘氨酸配合物时的平均粒径(104.0nm)。另外,随着Cu^(2+)浓度的增大,Si C晶圆的摩擦系数先增大后减小,在300μmol/L时达到最大,为0.6137。最后,随着压力的增大,MRR不断增加,但压力过大,使得Ra增大。随着抛光盘转速的增大,MRR先增大后减小,Ra无明显变化,在120 r/min时,MRR有最大值,为96 nm/h,Ra为0.161nm。结论 Cu^(2+)-甘氨酸配合物作为催化剂能够加快Si C化学机械抛光中的化学氧化速率,从而提高MRR,并且能够提高抛光液分散稳定性,改善Si C晶圆表面质量。另外,增大抛光压力可以增强机械磨削作用,提高MRR,但压力过大,会损伤晶片表面。抛光盘转速的增大也可以提高MRR,但其过大则会使抛光液外溅,降低化学作用,导致MRR降低。
The work aims to improve the material removal rate(MRR) and the surface quality of the Si-face 6H-SiC wafer by chemical mechanical polishing(CMP). CMP was performed on the Si-face of 6H-SiC wafer with a polishing slurry including the different concentrations of Cu2+ and glycine as catalysts and the hydrogen peroxide(H2O2) as an oxidant. The SiC wafer was weighed by a precision balance to calculate the MRR before and after polishing. AFM was used to observe the surface of the SiC wafer and the surface roughness(Ra) was measured. The Zeta potential and particle size distribution of the nano-silica abrasive particles were measured by a Zeta potential meter at different concentrations of Cu2+. The friction and wear tester was used to measure the friction coefficient of SiC wafer with different concentrations of Cu2+. The effects of different pressures and rotational speeds on the MRR and Ra of SiC during CMP were compared. With the increase of Cu2+ concentrations, the MRR increased firstly and then decreased. When the Cu2+ concentration was 300 μmol/L, the MRR had a maximum of 82 nm/h, and in this case, the Ra was 0.156 nm. In contrast, the MRR was 62 nm/h and the Ra was 0.280 nm without the addition of the Cu2+-glycine complex. At the same time, with the increase of the Cu2+ concentrations, on the one hand, the absolute values of the zeta potential of the abrasive particles in the slurry decreased, but was still higher than the absolute value of the zeta potential without the addition of the Cu2+-glycine complex;on the other hand, the average particle diameters of the abrasive particles gradually increased, but was still smaller than the average particle diameters(104.0 nm) without the addition of the Cu2+-glycine complex. In addition, as the Cu2+ concentration increased, the friction coefficient of the SiC wafer firstly increased and then decreased, reaching a maximum of 0.6137 at 300 μmol/L. Finally, as the pressure increased, the MRR increased gradually, but the Ra increased when the pressure was too high. With the increase of the polishing plate speed, the MRR increased firstly and then decreased, but there was no significant changes in the Ra. At the speed of 120 r/min, the MRR had a maximum of 96 nm/h with the Ra of 0.161 nm. As a catalyst, the Cu2+-glycine complex can accelerate the chemical oxidation rate in the CMP of SiC to increase the MRR, and can improve the dispersion stability of the slurry to make the surface quality of the SiC wafer better. In addition, increasing the polishing pressure can enhance the mechanical grinding effect and magnify the MRR, but if the pressure is too high, the wafer surface will be damaged. An increase in the rotational speed of the polishing plate can also increase the MRR, but if the speed is too high, the polishing solution will splash out, lowering the chemical effect and resulting in a decrease of the MRR.
作者
滕康
陈国美
倪自丰
钱善华
白亚雯
TENG Kang;CHEN Guo-mei;NI Zi-feng;QIAN Shan-hua;BAI Ya-wen(School of Mechanical Engineering,Jiangnan University,Wuxi 214122,China;School of Mechanical and Electrical Engineering,Wuxi Vocational Institute of Commerce,Wuxi 214153,China,Taihu University of Wuxi,Wuxi 214064,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第3期291-296,共6页
Surface Technology
基金
国家自然科学基金(51305166)~~
关键词
碳化硅
化学机械抛光
催化剂
材料去除率
表面粗糙度
粒径分布
silicon carbide
chemical mechanical polishing
catalyst
material removal rate
surface roughness
particle size distribution
