Computational Investigation of Ion Energy Angle Distribution within Trench Structures using the hPIC2 Particle-in-Cell Code

Plasma-materials interactions are sensitive to a plasma's ion energy-angle distribution (IEAD). Accurately characterizing the IEAD of a processing plasma can aid the use and development of pattern transfer methods used in high aspect ratio etching for MEMS and integrated circuits. In particular, the variation in ion flux in different areas of a microstructure can cause variation in etch rates. hPIC2, a GPU-accelerated electrostatic particle-in-cell code, is able to simulate plasmas in unstructured finite element meshes using the finite element C++ library, MFEM. This is used to model the geometry of various trench structures often found in etching process flows, enabling a spatially varying IEAD output. We investigate the effect of varying plasma parameters and aspect ratios on the IEAD incident on trench surfaces.