| AVS 61st International Symposium & Exhibition | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS-TuP |
| Session: | Plasma Science and Technology Poster Session |
| Presenter: | Leon Shohet, University of Wisconsin-Madison |
| Authors: | F.A. Choudhury, University of Wisconsin-Madison J.-F. de Marneffe, IMEC, KU Leuven Belgium M. Baklanov, IMEC, KU Leuven Belgium Y. Nishi, Stanford University J.L. Shohet, University of Wisconsin-Madison |
| Correspondent: | Click to Email |
During plasma processing, low-k dielectric films are exposed to high levels of vacuum ultraviolet (VUV) radiation emitted from the plasma. To reduce the dielectric constant of organosilicate (OSG) low-k materials, porosities (up to 50%) are introduced in the dielectric layer. The porous structure of these materials makes them even more sensitive to VUV modification due to their low density and deep penetration of photons into the film1. The effects of VUV photons on the chemical modification of OSG low-k materials as a function of porosity has been reported recently1 and showed that OSG films having high porosities undergo higher Si-CH3 depletion and severe chemical degradation. In this work, we investigate the changes to the electrical properties of porous low-k dielectrics as a function of porosity after VUV irradiation. VUV irradiation introduces defect states and generates trapped charges within the dielectric that can degrade the electrical properties of the film2. In order to investigate the influence of the porosity on the electrical properties after VUV exposure, organic low-k films of porosities between 15 and 50% were exposed to synchrotron VUV radiation of energies ranging from 6 to 15 eV and fluences up to 5 x 1014 photons/cm2 to find the most damaging photon energies. CV measurements showed an increase in the dielectric constant along with a flat-band voltage shift and the presence of hysteresis after VUV irradiation. Initial IV and TDDB measurements indicate an increase in leakage currents along with lower breakdown fields after VUV irradiation. It is likely that these effects will be a function of VUV photon energy.3
This work has been supported by the Semiconductor Research Corporation under Contract No. 2012-KJ-2359 and the National Science Foundation under Grant No. CBET-1066231.
References:
1 T. V. Rakhimova, A. T. Rakhimov, Yu. A. Mankelevich, D. V. Lopaev, A. S. Kovalev, A. N. Vasil’eva, O. V. Proshina, O. V. Braginsky, S. M. Zyryanov, K. Kurchikov, N. N. Novikova, and M. R Baklanov, Applied Physics Letters,102, 111902 (2013)
2 H. Sinha, J. L. Lauer, M. T. Nichols, G. A. Antonelli, Y. Nishi, and J. L. Shohet, Appl. Phys. Lett.96, 052901 (2010).
3 H. Sinha, H. Ren, M. T. Nichols, J.L. Lauer, M. Tomoyasu, N. M. Russell, G. Jiang, G. A. Antonelli, N.C. Fuller, S.U. Engelmann, Q.Lin, V. Ryan, Y. Nishi, and J. L. Shohet, (Focused Review), Applied Physics Reviews, Journal of Applied Physics112 11101 (2012)