Apparatus for detecting plasma etch endpoint in semiconductor fabrication and associated method

摘要

An apparatus for semiconductor processing reduces etch endpoint interference by analyzing the plasma while excluding reflections from the semiconductor wafer. The apparatus includes a chamber having a semiconductor substrate holder, a plasma generator, and a window. An optical fiber is connected to the window so as to be optically connected to the plasma from outside the chamber. A processor is connected to a second end of the optical fiber for analyzing the plasma. The window has a substantially planar portion and a substantially tubular portion extending outwardly therefrom. The tubular window portion has a closed end opposite the planar window portion, and the optical fiber is connected to the closed end of the tubular window portion. The tubular window portion is positioned at a predetermined angle relative to the planar window portion so as to be optically coupled to view the plasma, while avoiding reflections from the semiconductor substrate to thereby reduce the interference.