【作者】 王海波；

【导师】 宋晓岚；

【作者基本信息】 中南大学 ， 材料学， 2005， 硕士

【摘要】 纳米CeO₂因具有多方面功能特性,在很多领域得到广泛应用。最新研究表明,纳米CeO₂可用于集成电路芯片加工的化学机械抛光（CMP）浆料。以纳米CeO₂代替SiO₂作为硅片和SiO₂介质层CMP过程的研磨粒子,具有平整质量更高、抛光速率更快、选择性更好的优点。 在CMP技术中纳米研磨粒子在液相介质中的充分分散是保证抛光质量的前提,本文研究了纳米CeO₂在不同条件下水相体系中表面电性及分散性。结果表明:酸性水介质中,CeO₂表面带正电,且pH为4左右时Zeta电位最大;碱性水介质中,CeO₂表面带负电,且pH为11左右时Zeta电位绝对值最大,CeO₂等电点pH值约为6.8左右。 本文选用非离子型分别与阳离子型和阴离子型表面活性剂进行复配,通过测定混合表面活性剂体系中纳米CeO₂颗粒表面Zeta电位、吸附等温线以及沉降实验,研究了混合表面活性剂对纳米CeO₂分散稳定的协同效应。结果表明:在不同pH值条件下和不同混合表面活性剂体系中纳米CeO₂颗粒表现出不同的表面电性,从而影响其分散稳定行为;加入混合表面活性剂后,等电点明显迁移,Zeta电位改变,其中加入Tween80与CTAB组成的非离子型与阳离子型混合表面活性剂,使纳米CeO₂颗粒表面Zeta电位越过等电点,在广泛的pH值范围内均为正值;Tween80与SDBS组成的非离子型与阴离子型混合表面活性剂体系中纳米CeO₂颗粒表面Zeta电位等电点移向低pH方向;纳米CeO₂颗粒对两种混合表面活性剂均有良好的吸附性能,但两者吸附等温线形式有所不同,Tween 80与CTAB体系中表面活性剂浓度达CMC后,其吸附量趋于下降;Tween 80与SDBS体系中表面活性剂浓度达一定值后,其吸附量达饱和并趋于稳定;纳米CeO₂颗粒在混合表面活性剂体系中的分散稳定性较未添加表面活性剂时均有明显的改善,其中Tween 80与SDBS混合表面活性剂体系对纳米CeO₂悬浮液的分散稳定性的协同作用更明显。混合表面活性剂对浆料分散稳定效果的影响主要取决于各表面活性剂之间的相互作用。更多还原

【Abstract】 Because of having lots of functional characters, CeO₂ nanoparticles have been applied widely in many fields of high technology. Recent investigation shows that CeO₂ nanoparticles can be used as CMP slurry to polish IC chip. As abrasive particles for silicon wafer and silica dielectric layer in CMP process, CeO₂ nanoparticles have more advantages of higher smoothness, higher velocity and better selectivity than SiO₂ nanoparticles.In CMP technology, abrasive particles which disperse fully in the liquid is the premise to ensure the quality of CMP.In this paper, surface charge potential and dispersion property of CeO₂ nanoparticles in the water under different conditions are researched furtherly. In the acidic water, it shows that surface of CeO₂ nanoparticles has positive charge and Zeta potential is most at pH 4 or so. While in the alkalescent water, surface of CeO₂ nanoparticles has negative charge, and absolute value of Zeta potential is most at pH 11 or so,pH_IEP of CeO₂ is about 6.7.In this paper, the synergistic effect of the surfactant mixture was studied by the Zeta potential, adsorption experiment and settling experiment. After researching, it was found that CeO₂ particles have different surfactant electrical property in different pH value or mixture surfactant system, by which the dispersion stability was affected. Isoelectric point and Zeta potential was changed obviously by adding mixture surfactant. After adding the mixture surfactant that was made of Tween 80 and CTAB. The Zeta potential of CeO₂ particles was changed to be positive value under wide range pH value. Isoelectric point of Zeta potential move to lower pH value in the system that was added the mixture surfactant of Tween 80 and SDBS. CeO₂ particles have good adsorption property for these two kinds mixture surfactants. But the shapes of adsorption isotherm of them have different. The dispersion stability of CeO₂ particles in mixture surfactant system was improved obviously compare of no surfactant. The synergistic effect of mixture surfactant of Tween 80 and SDBS on CeO₂ slurry was more obviously than the other one. Affect of mixture surfactant on dispersion stability was decided by interact of single surfactants.更多还原