In-situ spatially resolved plasma monitoring by using optical emission spectroscopy

摘要

Implementations of the present disclosure relate to a plasma chamber having an optical device for measuring emission intensity of plasma species. In one implementation, the plasma chamber includes a chamber body defining a substrate processing region therein, the chamber body having a sidewall, a viewing window disposed in the sidewall, and a plasma monitoring device coupled to the viewing window. The plasma monitoring device includes an objective lens and an aperture member having a pinhole, wherein the aperture member is movable relative to the objective lens by an actuator to adjust the focal point in the plasma using principles of optics, allowing only the light rays from the focal point in the plasma to reach the pinhole. The plasma monitoring device therefore enables an existing OES (coupled to the plasma monitoring device through an optical fiber) to monitor emission intensity of the species at any specific locations of the plasma.