18 December 2014 The chemistry screening for ultra low-k dielectrics plasma etching
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Proceedings Volume 9440, International Conference on Micro- and Nano-Electronics 2014; 944002 (2014) https://doi.org/10.1117/12.2181010
Event: The International Conference on Micro- and Nano-Electronics 2014, 2014, Zvenigorod, Russian Federation
Nowadays, some of the important problems in microelectronics technological node scaling down are related to interconnect delay, dynamic power consumption and crosstalk. This compels introduction and integration of new materials with low dielectric permittivity (low-k materials) as insulator in interconnects. One of such materials under consideration for sub 10 nm technology node is a spin-coated organosilicate glass layer with ordered porosity (37-40%) and a k-value of 2.2 (OSG 2.2). High porosity leads to significant challenges during the integration and one of them is a material degradation during the plasma etching. The low-k samples have been etched in a CCP double frequency plasma chamber from TEL. Standard recipes developed for microporous materials with k<2.5 and based on mixture of C4F8 and CF4 with N2, O2 and Ar were found significantly damaging for high-porous ULK materials. The standard etch recipe was compared with oxygen free etch chemistries based on mixture CF4 with CH2F2 and Ar assuming that the presence of oxygen in the first recipe will have significant negative impact in high porous ULK materials. The film damage has been analyzed using FTIR spectroscopy and the k-value has been extracted by capacitance CV-measurements. There was indirectly shown that vacuum ultraviolet photons cause the main damage of low-k, whereas radicals and ions are not so harmful. Trench structures have been etched in low-k film and cross-SEM analysis with and without HF dipping has been performed to reveal patterning capability and visualize the sidewall damage and. The bottom roughness was analyzed by AFM.
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A. Zotovich, A. Zotovich, M. Krishtab, M. Krishtab, F. Lazzarino, F. Lazzarino, M. R. Baklanov, M. R. Baklanov, } "The chemistry screening for ultra low-k dielectrics plasma etching", Proc. SPIE 9440, International Conference on Micro- and Nano-Electronics 2014, 944002 (18 December 2014); doi: 10.1117/12.2181010; https://doi.org/10.1117/12.2181010

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