Modeling Study of Laser Beam Scattering by Defects on Semiconductor Wafers

TL;DR

This study models laser beam scattering by nanometer-scale defects on semiconductor wafers, using advanced electromagnetic simulations to accurately predict scattering patterns and effects of defect shape and orientation.

Contribution

It introduces a high-accuracy electromagnetic modeling approach for complex defect geometries on wafers, surpassing previous methods.

Findings

Accurate scattering patterns for spherical defects were obtained.

Ellipsoidal defect orientation significantly affects scattering.

Results enable better defect detection in semiconductor manufacturing.

Abstract

Accurate modeling of light scattering from nanometer scale defects on Silicon wafers is critical for enabling increasingly shrinking semiconductor technology nodes of the future. Yet, such modeling of defect scattering remains unsolved since existing modeling techniques fail to account for complex defect and wafer geometries. Here, we present results of laser beam scattering from spherical and ellipsoidal particles located on the surface of a silicon wafer. A commercially available electromagnetic field solver (HFSS) was deployed on a multiprocessor cluster to obtain results with previously unknown accuracy down to light scattering intensity of -170 dB. We compute three dimensional scattering patterns of silicon nanospheres located on a semiconductor wafer for both perpendicular and parallel polarization and show the effect of sphere size on scattering. We further computer scattering patterns of nanometer scale ellipsoidal particles having different orientation angles and unveil the effects of ellipsoidal orientation on scattering.