| AVS 62nd International Symposium & Exhibition | |
| Electronic Materials and Processing | Thursday Sessions |
| Session EM-ThM |
| Session: | Interconnects II |
| Presenter: | Faraz Choudhury, University of Wisconsin-Madison |
| Authors: | F. Choudhury, University of Wisconsin-Madison J.-F. de Marneffe, IMEC, Belgium M. Baklanov, IMEC, Belgium S.W. King, Intel Corporation Y. Nishi, Stanford University J.L. Shohet, University of Wisconsin-Madison |
| Correspondent: | Click to Email |
During various stages of plasma processing, low-k dielectrics are exposed to high levels of VUV radiation emitted from the plasma. Modern ultra-low-k materials have interconnected pores within the dielectric layer that make them susceptible to damage due to their low density and deep penetration of active species into the film. In this work, VUV induced degradation of low-k dielectrics as a function of porosity is investigated. Organosilicate low-k films of porosities between 15% (k=2.7) and 50% (k=1.9) were exposed to synchrotron VUV radiation with energies ranging from 6 -12eV. Both electrical and chemical properties of the films were analyzed to find the most damaging spectral region. FTIR spectra showed increased depletion of the methyl group after VUV irradiation as a function of film porosity and CV measurements showed an increase in the dielectric constant along with a flat-band voltage shift. IV characteristics of the VUV irradiated porous films indicated an increase in leakage currents and lower breakdown voltage. The degree of damage is higher for the more porous films indicating that the introduction of pores deteriorate the electrical properties of the low-k films. The higher leakage currents in the more porous films were attributed to more porogen residues within the dielectric layer. To remove the porogen residues, the films are treated with hydrogen downstream plasma at 300O C. FTIR measurements confirm removal of porogen residues and leakage currents are significantly reduced after the hydrogen-annealing process.
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] K. Maex, M.R. Baklanov, D. Shamiryan, F. Iacopi, S.H. Brongersma, and Z.S. Yanovitskaya, J. Appl. Phys. 93, 8793 (2003)