静电自组装制备复合磨粒及其 对铜的抛光特性研究

研究苯代三聚氰胺甲醛（BGF）微球与阳离子型聚电解质聚二烯丙基二甲基氯化铵（PDADMAC）、阴离子型聚电解质聚4－苯乙烯璜酸钠（PSS）之间的吸附特性，利用静电自组装技术改变和控制BGF微球的荷电特性，制备出不同形式的PEi BGF/SiO2复合磨粒，以Zeta电位、透射电子显微镜（TEM）和热重分析（TG）等手段对复合磨粒进行了表征，并利用这些复合磨粒制备了铜片抛光用的复合磨粒抛光液。抛光试验表明，吸附在聚合物微球表面和游离于抛光液中的SiO2磨粒在抛光中均起到材料去除作用。传统单一SiO2磨粒抛光液的铜材料去除率为264 nm/min，PE0 BGF/SiO2混合磨粒抛光液的铜材料去除率为348 nm/min，PE3 BGF/SiO2复合磨粒抛光液的铜材料去除率为476 nm/min。经上述3种抛光液抛光后的铜表面，在5 μm×5 μm范围内，表面粗糙度Ra从0.166 μm分别降至3.7 nm、2.6 nm和1.5 nm，峰谷值Rpv分别小于20 nm、14 nm和10 nm，复合磨粒抛光液对铜片有良好的抛光性能。

Preparation of composite abrasives by electrostatic self assembly method and its polishing properties in Cu chemical mechanical polishing

The absorption characteristics of cationic polyelectrolyte PDADMAC and anionic polyelectrolyte PSS on benzoguanamine formaldehyde(BGF) particles are investigated.The charging characteristics of BGF particles are changed and controlled using electrostatic self-assembly method.A variety of PEi-BGF/SiO2 composite abrasives are obtained.The as-prepared samples are analyzed by Zeta potential analysis,transmission electron microscope(TEM) and thermogravimetric(TG) analysis.The composite abrasives slurries are prepared for copper polishing.The polishing results indicate that it is SiO2 abrasives,not only coated SiO2 abrasive on polymer particles but also free SiO2 abrasive in slurry,that offer the polishing action.The material removal rates of copper polishing are 264 nm/min,348 nm/min and 476 nm/min using single SiO2 abrasive slurry,PE0-BGF/SiO2 mixed abrasives slurry and PE3-BGF/SiO2 composite abrasives slurry respectively.The surface roughness Ra of copper wafer(with 5 μm×5 μm district) is decreased from 0.166 μm to 3.7 nm,2.6 nm and 1.5 nm,and the surface peak-valley values Rpv are less than 20 nm,14 nm and 10 nm using these kinds of slurries respectively.