Modeling ellipsometric measurement of three-dimensional structures with rigorous coupled wave analysis and finite element method simulations

Perspective: Optical measurement of feature dimensions and shapes by scatterometry

“…Here, the sensitivity increase is obtained through the wavelength shift for a plasmon-induced spectral feature with change in linewidth, and we refer to that sensitivity increase in this section. 19,20 This issue is illustrated in Fig. 15 using the simulated change in the M 12 Mueller matrix element with the copper linewidth.…”

“…the wider grating and the pitch of the narrower grating to obtain the maximum sensitivity to linewidth variation over the wavelength range of the ellipsometer especially when the wavelength range extends in the IR to 1500 nm. [19][20][21] Although the original concept was based on surface plasmon polaritons, O'Mullane et al found that a copper plate below the cross-grating resulted in localized plasmons between the top grating and copper plate that enhanced sensitivity to the copper linewidth. 19,20 These simulations were based on both RCWA and the finite element method.…”

“…[19][20][21] Although the original concept was based on surface plasmon polaritons, O'Mullane et al found that a copper plate below the cross-grating resulted in localized plasmons between the top grating and copper plate that enhanced sensitivity to the copper linewidth. 19,20 These simulations were based on both RCWA and the finite element method. The cross-grating structure is shown in Fig.…”

“…In order to improve sensitivity to linewidth changes, O'Mullane, et al employed a cross-grating plasmonic structure that changed reflection in a manner that increased sensitivity to the linewidth of copper interconnect lines. [19][20][21] The cross-grating test structure uses a grating that has the dimensions and pitch (periodicity) that result in surface plasmon polaritons when the light of appropriate wavelength from the ellipsometer scatters from the grating at an operational angle of incidence of 65 • . [19][20][21] The linewidth features in the surface plasmonic grating are larger than the state-of-the-art copper interconnect linewidths.…”

“…[19][20][21] The cross-grating test structure uses a grating that has the dimensions and pitch (periodicity) that result in surface plasmon polaritons when the light of appropriate wavelength from the ellipsometer scatters from the grating at an operational angle of incidence of 65 • . [19][20][21] The linewidth features in the surface plasmonic grating are larger than the state-of-the-art copper interconnect linewidths. the wider grating and the pitch of the narrower grating to obtain the maximum sensitivity to linewidth variation over the wavelength range of the ellipsometer especially when the wavelength range extends in the IR to 1500 nm.…”