| AVS 64th International Symposium & Exhibition | |
| Electronic Materials and Photonics Division | Thursday Sessions |
| Session EM-ThP |
| Session: | Electronic Materials and Photonics Poster Session |
| Presenter: | Ha Nguyen, University of Wisconsin-Madison |
| Authors: | H.M. Nguyen, University of Wisconsin-Madison F.A. Choudhury, University of Wisconsin-Madison C. Lee, National Tsing Hua University, Taiwan, Republic of China Y. Lin, National Synchrotron Radiation Research Center, Taiwan, Republic of China H. Fung, National Synchrotron Radiation Research Center, Taiwan, Republic of China C. Chen, National Synchrotron Radiation Research Center, Taiwan, Republic of China J. Blatz, University of Wisconsin-Madison D.I. Benjamin, University of Wisconsin-Madison W. Li, University of Wisconsin-Madison J.L. Shohet, University of Wisconsin-Madison |
| Correspondent: | Click to Email |
During plasma processing, dielectric films used in the semiconductor technology are often exposed to large doses of vacuum ultraviolet (VUV) radiation and free radicals that can damage the dielectric material. In this work, we utilize specular x-ray reflectivity to measure the depth of damage of dielectric films as a function of energy of VUV photons and various doses of oxygen radicals. First, we examine the VUV-absorption spectrum of low-k organosilicate glass (OSG) using specular X-ray reflectivity (XRR). Low-k SiCOH films were exposed to synchrotron VUV radiation with energies ranging from 7 to 25 eV and the density depth profile of the VUV-irradiated films were extracted from the fitting of the XRR experimental data. The results show that the depth of the VUV-induced damage layer is a function of photon energy. Between 7 and 11 eV, the depth of the damaged layer decreases sharply from 110 nm to 60 nm and then gradually increases to 85 nm at 21 eV. The maximum VUV absorption in the OSG films occurs between 11 and 15 eV. Next, SiO2 dielectric films were exposed to oxygen plasma in an electron cyclotron resonance plasma reactor and XRR measurements were made in order to determine the depth of damage as a function of oxygen-radical dose. It was found that the depth of damage increases as a function of plasma exposure time and eventually saturates to ~ 66 nm after about 30 minutes of oxygen-plasma exposure. This work shows that XRR damage depth profiling can be a very effective, non-destructive tool to determine the penetration depth of VUV photons and other plasma reactive species in dielectric films [1].
This work was supported by the Semiconductor Research Corporation under contract 2012-KJ-2359.
[1] Faraz A. Choudhury et al. “Oxygen radical transmission through and damage to freestanding single and multilayer dielectric films” AVS 64th International Symposium & Exhibition, Tampa, Florida (2017).