We have investigated the contributions of surface effects to Monte Carlo simulations of top-down scanning electron microscopy (SEM) images. The elastic and inelastic scattering mechanisms in typical simulations assume that the electron is deep in the bulk of the material. In this work, we correct the inelastic model for surface effects. We use a model for infinite flat surfaces, and apply it to non-flat, but smooth, geometries. Though this is a simplification, it captures most qualitative differences to the bulk model, including coupling to surface plasmons. We find that this correction leads to an increased SE signal near a feature's sidewall in low-voltage critical dimension SEM (CD-SEM). The effect is strongest for low beam energies. Due to some of the assumptions in our model, we are unable to quantitatively predict the extent by which the signal from the sidewall is enhanced. The enhancement of signal from the sidewall may be large enough to cause the measured edge position to shift significantly.
|Title of host publication||Proceedings of SPIE|
|Subtitle of host publication||Metrology, Inspection, and Process Control for Microlithography XXXIII|
|Editors||Vladimir A. Ukraintsev, Ofer Adan|
|Number of pages||16|
|Publication status||Published - 2019|
|Event||Metrology, Inspection, and Process Control for Microlithography XXXIII 2019 - San Jose, United States|
Duration: 25 Feb 2019 → 28 Feb 2019
|Name||Metrology, Inspection, and Process Control for Microlitography XXXIII|
|Conference||Metrology, Inspection, and Process Control for Microlithography XXXIII 2019|
|Period||25/02/19 → 28/02/19|
Bibliographical noteGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
- Monte Carlo simulation
- Scanning electron microscopy
- Surface plasmons