In situ electrical characterization of dielectric thin films directly exposed to plasma vacuum-ultraviolet radiation

In this article we report a method for in situ electrical characterization of dielectric thin films under direct exposure to plasma in an electron-cyc lotron-resonance etcher. This method is based on the development of a speci al test structure that allows for the measurement of the influence of plasm a vacuum-ultraviolet (VUV) radiation on the electrical conductivity of thin dielectric layers. Results show that the measured conductivity of SiO2 lay ers temporarily increases during exposure to argon and oxygen plasmas, with controlled VUV emission. Based on the measurements made through this metho d, a model of the VUV-induced conductivity of SiO2 is developed. These meas urements are very important for plasma processing of semiconductor devices, because the temporary increase in the conductivity of these layers upon ex posure to processing plasmas can decrease the plasma-induced charging of th ese dielectric layers depending on the intensity of the plasma VUV emission . This can have an impact on the properties and reliability of processed de vices. (C) 2000 American Institute of Physics. [S0021-8979(00)03016-4].