A global model for C₄F₈plasmas coupling gas phase and wall surface reaction kinetics

Abstract

A global or zero-dimensional model for C4F8 plasmas is formulated by coupling gas phase and wall surface reaction kinetics. A set of surface reactions implements experimental findings and quantifies the effect of the fluorocarbon film formed on the reactor walls on the densities of species in the gas phase. The model allows the calculation of the pressure change after the ignition of the discharge and the effective sticking (surface loss) coefficients of the neutral species on the wall surface. The model is validated by comparison with experimental measurements, i.e. pressure rise and densities of F atoms, CF2 and CF radicals, in an inductively coupled plasma reactor. It is predicted that C4F8 is vastly dissociated and CF4 becomes the dominant species even at low power conditions. A net production of CF3 radical and a net consumption of CF2 radical at the reactor walls are predicted. A study on the contribution of each reaction to the production and consumption of the species shows that at least one surface reaction is among the major sinks or sources of CF4, CFx radicals and F.

Kinetics of the deposition step in time multiplexed deep silicon etches

“…The ion-enhanced nature of the film deposition process has been studied previously [17][18][19][20][21] so it should not be surprising that it is seen here. The ion-enhanced nature of the film deposition process has been studied previously [17][18][19][20][21] so it should not be surprising that it is seen here.…”

“…Kokkoris et al have performed such modeling. 5,21 The key point to notice in Fig. 5, which shows that molecular flux to the bottom center of a trench as a function of both the trench aspect ratio and the sticking coefficient ("SC" ¼ sticking probability) for the molecule being modeled.…”

Gain and loss mechanisms for neutral species in low pressure fluorocarbon plasmas by infrared spectroscopy

“…5 With this reasoning, the continuity equation for c-C 4 F 8 steady-state density can be simplified to Gain and loss mechanisms for c-C 4 F 8 Analysis of the gain and loss processes contributing to the aforementioned steady-state values will begin with the parent gas, c-C 4 F 8 .…”

Controlling Asymmetric Photoresist Feature Dimensions during Plasma-Assisted Shrink

“…[21] C 4 F 8 molecules in the plasma are dissociated into FC film precursors that deposit onto plasma facing surfaces. [22] The composition, etch, and deposition rates, and thickness are determined by plasma parameters such as depositing gas chemistry/ concentration, plasma density, ion energy, etc. [20] Fluorocarbon film deposition is highly dependent on depositing species fluxes, and reactivity of surface sites.…”