| AVS 60th International Symposium and Exhibition | |
| Plasma Science and Technology | Monday Sessions |
| Session PS-MoA |
| Session: | Advanced BEOL/Interconnect Etching |
| Presenter: | T.A. Pomorski, Penn State University |
| Authors: | T.A. Pomorski, Penn State University P.M. Lenahan, Penn State University M. Mutch, Penn State University S.W. King, Intel Corporation |
| Correspondent: | Click to Email |
Low-κ interlayer dielectrics with dielectric constants significantly less then those of SiO2 and are utilized to reduce capacitance induced RC delays in ULSI circuits. [1,2] At the present time, very little is known about the underlying physical mechanisms involved in electronic transport within these films. Recent electron paramagnetic resonance (EPR) studies have reported on defect centers in some of these films [3,4]. In one study, comparisons were made between EPR defect densities and leakage currents before and after exposure to UV light under conditions generally similar to those during industrial UV curing. That study noted that large UV induced changes in spin density were accompanied by large changes in dielectric leakage, suggesting a link between the defects and leakage.[3] In this study we have conducted a considerable more extensive survey specifically focused upon low-k SiOC:H films. We find that a large variety of paramagnetic centers are present in the dielectrics and that both the types of defects present and the defect densities are quite strong functions of processing parameters. Defects include silicon dangling bond centers in which the silicon is back bonded to three oxygens (E” centers), silicon dangling bond centers complexed to a single hydrogen atom, a dangling bond center complexed to three equivalent hydrogens, and very likely carbon dangling bond centers. In, limited cross section of samples, all with the EPR dominated by a center with a zero crossing g=2.0026 +/- 0.0003 and all similarly processed, we observe strong correlation between defect density and dielectric leakage currents. It should be noted that quite recent SiOC:H studies which have utilized another analytical approach has also identified the presence of E’ centers in similar films. King et. al. recently reported on reflection electron energy loss spectrometry (REELS) on similar dielectric films and noted the presence of REELS spectra consistent with E’ centers a result which our EPR data supports.[5]
[1] K. Maex, D. Shamiryan, F. Iacopi, S.H. Brongersma, and Z.S. Yanovitskaya, J. Appl. Phys, 93, 11 (2003).
[2] W. Volksen, R.D. Miller, and G. Dubois, Chem Rev. 110, 56 (2010).
[3] B. Bittel, P. Lenahan, S. King, Appl. Phys. Lett. 97, 6 (2010)
[4] H. Ren, et. al. Appl. Phys. Lett. 98, 10 (2011)
[5] S.W. King, B. French, E. Mays, J. Appl. Phys, 113, 044109 (2013)