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以采用改进无皂乳液聚合法制备的纳米尺寸聚苯乙烯(PS)微球为内核,采用原位化学沉淀法制备了不同壳层厚度的PS/CeO2核/壳包覆结构复合微球。将所制备的复合颗粒用于二氧化硅介质层的化学机械抛光,用原子力显微镜测定晶片的微观形貌和粗糙度。电镜结果表明:复合颗粒呈规则球形,其PS内核尺寸约为72 nm,CeO2壳厚为5~20 nm。抛光结果显示:在本实验范围内,抛光速率随抛光压力的增加而增大,而过低(2.4 psi,1 psi=6 895 Pa)或过高(6.1 psi)的抛光压力均使晶片表面产生划痕。当抛光压力适中(4.5 psi)时,经复合磨料(壳厚约为13 nm)抛光后的晶片表面无明显划痕,在5μm×5μm范围内表面均方根粗糙度为0.265 nm,抛光速率达98.7 nm/min。
The PS / CeO2 core / shell composite microspheres with different shell thickness were prepared by in-situ chemical precipitation method using nanosized polystyrene (PS) microspheres prepared by modified soap-free emulsion polymerization as the core. The prepared composite particles were used for chemical mechanical polishing of a silicon dioxide dielectric layer, and the microstructure and roughness of the wafer were measured by atomic force microscopy. Electron microscopy results show that the composite particles have a regular spherical shape with a PS core size of about 72 nm and a CeO2 shell thickness of 5-20 nm. Polishing results show that within the experimental range, the polishing rate increases with increasing polishing pressure, while too low (2.4 psi, 1 psi = 6 895 Pa) or excessively high (6.1 psi) polishing pressure results in wafer surface Scratches. When the polishing pressure is moderate (4.5 psi), there is no obvious scratches on the surface of the wafer polished by the composite abrasive (shell thickness is about 13 nm). The root mean square roughness in the range of 5 μm × 5 μm is 0.265 nm. The polishing rate 98.7 nm / min.