等离子体刻蚀中边缘离子轨迹的控制与优化

由于常规等离子体刻蚀系统在晶圆边缘处的阻抗与晶圆中心处的阻抗不一致, 使离子在晶圆边缘处的运动轨迹发生偏移, 很难满足越来越高的刻蚀工艺均匀性及深宽比的要求。本文提出一种通过调整晶圆边缘阻抗进行边缘离子运动方向优化的方法, 可以连续实时地调整边缘离子的运动轨迹, 实现对边缘离子运动方向的控制。研究结果表明, 离子的运动方向可以被优化为垂直于晶圆表面, 从而能获得良好的刻蚀速率均匀性及垂直的刻蚀形貌。

Active Ion-Trajectory Control at the Wafer Extreme Edge in Plasma Etch

As the impedance of the conventional plasma etching system at the edge of the wafer is not consistent with that at the center of the wafer, the movement trajectory of ions at the edge of the wafer is deviated and it is difficult to meet the more stringent requirements on etching process uniformity and high aspect ratio. A method to optimize the movement direction of edge ions by adjusting the impedance of the wafer edge is proposed which can continuously and real-time adjust the movement trajectory of edge ions and control the direction of edge ions. The results show that the direction of ion movement can be optimized to be perpendicular to the surface of the wafer, the uniformity of the edge etch rate is optimized, and the vertical etching morphology is obtained.