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重掺衬底硅片在经历高温外延加工过程中,硅片边缘的损伤会在硅片的外延层上形成位错缺陷。对边缘初始状态一致的直径为200 mm硅单晶片进行酸腐蚀、机械抛光、化学机械抛光及机械抛光加化学机械抛光等不同条件下的边缘抛光实验,使用显微镜观察抛光片的边缘形貌,使用三维光学表面分析仪对抛光片的表面粗糙度进行测量,之后对抛光后的样品进行外延加工,对比经过不同加工方式的抛光后硅片边缘损伤的残留程度。结果表明,酸腐蚀能够去除硅片边缘绝大部分的损伤,机械抛光会重新带入机械损伤,机械抛光后再进行化学机械抛光能彻底消除硅片边缘的损伤层,但相对成本较高。化学机械抛光也能够彻底去除硅片边缘的损伤层,是大尺寸衬底硅片边缘抛光的最优加工工艺。
Heavily doped substrate wafer in the process of high temperature epitaxial processing, the edge of the silicon wafer damage in the epitaxial layer of silicon to form dislocation defects. Edge polishing experiments were performed under different conditions, such as acid etching, mechanical polishing, chemical mechanical polishing, mechanical polishing and chemical mechanical polishing, with a diameter of 200 mm on the edge of the silicon wafer. The edge morphology of the polished wafer was observed by using a microscope. The three-dimensional optical surface analyzer measured the surface roughness of the polished wafer, followed by epitaxial processing of the polished sample to compare the residual damage of the wafer edge damaged by the different processing methods. The results show that acid etching can remove most of the damage on the edge of silicon wafer, and mechanical polishing can bring the mechanical damage again. After mechanical polishing, the chemical mechanical polishing can completely eliminate the damage layer at the edge of silicon wafer, but the relative cost is higher. Chemical mechanical polishing can also completely remove the damaged layer on the edge of the silicon wafer, which is the optimal processing technology for polishing the edge of a large-size silicon substrate.