The surface charging effects in three‐dimensional simulation of the profiles of plasma‐etched nanostructures

Abstract

SUMMARYParticles and fields represent two major modeling paradigms in pure and applied science at all. Particles typically exist in a spatial domain and they may interact with other particles or with field quantities defined on that domain. A field, on the other hand, defines a set of values on a region of space. In this paper, a methodology and some of the results for three-dimensional (3D) simulations that includes both field and particle abstractions are presented. In our studies, charging damage to a semiconductor structure during plasma etching is simulated by using 3D level set profile evolution simulator. The surface potential profiles and electric field for the entire feature were generated by solving the Laplace equation using finite elements method. Calculations were performed in the case of simplified model of Ar 1 /CF 4 non-equilibrium plasma etching of SiO 2 .

Roughness Evolution and Charging in Plasma-Based Surface Engineering of Polymeric Substrates: The Effects of Ion Reflection and Secondary Electron Emission

“…Models for the reflection of ions on surfaces have been proposed [ 47 , 48 , 49 , 50 , 51 , 52 , 53 ] in the context of plasma etching of conventional structures of microelectronics (trenches and holes) to study etching artifacts due to surface charging, such as notching [ 47 ], twisting [ 53 ], and microtrenching [ 48 ]. Hwang and Giapis [ 47 , 48 ] assumed inelastic and specular reflection model for Si and silicon-on-insulator (SOI) substrates, following hard sphere collision kinematics.…”

“…Specular and elastic reflection was considered by Zhao et al [ 49 ] for photoresist and SiO 2 substrates. Radmilovic-Radjenovic et al [ 50 ] also considered specular reflection for SiO 2 substrates. Wang and Kushner [ 53 ] considered both specular (at high energies) and diffusive (at low energies) reflection for SiO 2 substrates.…”

“…Wang and Kushner [ 53 ] considered both specular (at high energies) and diffusive (at low energies) reflection for SiO 2 substrates. In all of the previous works [ 47 , 48 , 49 , 50 , 51 , 52 , 53 ] it was considered that the incident ions deposited their charge and were reflected as hot neutral species.…”

The Implementation of the Surface Charging Effects in Three-Dimensional Simulations of SiO<sub>2</sub> Etching Profile Evolution

“…The difference causes the electron shading effect at the etched feature, thus generating positive potential at the deep trench bottom. This charging effect induces many serious plasma process induced damage problems such as bowing, trenching, reactive ion etching lag, and notching [5]. The reduction in the device size and multilayer structures requires a high-aspect ratio in the SiO 2 etching.…”

A hybrid modeling framework for simulating plasma-surface interactions of rough polymeric substrates

“…The need to remedy these artifacts has been the motive for several theoretical and computational studies on surface charging. The majority of them focus on dielectric, mainly Silicon dioxide Twisting Etching lag (SiO2) trenches or holes [130][131][132][133][134][135][136][137][138][139][140][141], some of them on Si trenches with a dielectric mask [142][143][144] and/or on SOI wafers [120,145,146].…”