IOP Publishing, Journal of Physics D: Applied Physics, 39(48), p. 395202
DOI: 10.1088/0022-3727/48/39/395202
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CF3I was suggested as a replacement of CF4 gas to decrease the plasma-induced damage (PID) on low-k dielectrics during etching. This proposal is investigated by means of plasma emission measurements and material characterisation. The experiments were conducted in a 300 mm capacitively coupled plasma source. The vacuum ultraviolet (VUV, nm) plasma emission was measured for discharges generated in a pure or a mixture of argon, CF4 and/or CF3I, since VUV plays a major role in PID. However, CF3I containing discharges were found to have a stronger emission than CF4 in the VUV range. Nevertheless, Fourier transform infra-red spectroscopy and κ-value measurements showed that there is almost no difference between the damage caused by CF3I or CF4 containing plasmas, while etching in a capacitively coupled plasma source. It is proposed that the damage caused by CF3I with lower F∗-density but higher VUV-photon flux is similar to the damage caused by CF4, with higher F∗-density but lower VUV-photon flux.