Modeling of implantation and mixing damage during etching of SiO2 over Si in fluorocarbon plasmas

Abstract

Energetic ion bombardment during plasma etching of microelectronics devices is necessary to activate chemical process and define features through the ions' anisotropic trajectories. These energetic fluxes can also cause damage and mixing of the constituents of crystalline lattices. These properties are likely best modeled using molecular dynamics (MD) simulations. The computational expense of these techniques makes feature scale simulations difficult, and so motivates development of approximate methods that can be used to model full features. In this regard, an implantation and mixing model has been developed and implemented into a Monte Carlo feature profile model to simulate the mixing and damage to the underlying Si during high aspect ratio (HAR) etching of SiO 2 trenches. Fluxes to the surface were provided by a reactor scale model. The feature scale model was validated by comparison to the mixing produced by Ar þ bombardment of Si with and without F and CF fluxes as predicted by MD simulations. Scaling of mixing damage of underlying Si during HAR of SiO 2 etching in Ar/C 4 F 8 /O 2 plasmas for rf bias powers of 1-4 kW was investigated. The authors found that mixing damage at the bottom of HAR features, though increasing in magnitude with increasing ion energy, does not scale as dramatically as on flat surfaces. This is due to the reflection of ions off of sidewalls which moderate the ion energies.

Overview of atomic layer etching in the semiconductor industry

“…17 Meanwhile, incoming ions and reactant species progressively "blur" the surface, forming a thick mixed layer characterized by increased roughness, mixed composition of reactant and substrate atoms, dangling bonds, and voids. 18,19 Uninhibited reactivity with continuous bombardment degrades postetch surface quality and can impact device performance. 3 While the mixed layer could be reduced with lower ion energy, 18,20 the paradox is that the layer is produced by the same high ion energies needed to perform etching in the first place.…”

Effects of feedstock availability on the negative ion behavior in a C4F8 inductively coupled plasma

“…The model was developed by Kushner and his team. [23][24][25] It is composed of several modules and can be used to investigate the electron behavior (like non-local 26 and harmonic effects 27 ), the chemical characteristics (like the chemical composition 28 ) and the surface kinetics (like etching, deposition, and implantation 29 ). In this work, the three main modules are applied, i.e., the Fluid Kinetics Module (FKM), the Electron Energy Transport Module (EETM), and the Electromagnetic Module (EMM).…”

Ion distribution functions at the electrodes of capacitively coupled high-pressure hydrogen discharges

“…The experimentally obtained shape of the IDF is benchmarked by the outcome of simulations using the Hybrid Plasma Equipment Model (HPEM) [39][40][41] by Mark Kushner's group. This two-dimensional simulation tool consists of several modules which address different physical phenomena.…”