Study On Ion Energy And Angular Distribution On Electrodes During Pulsed Plasma Etching Processes

Semiconductor integrated circuit is the highlight of the micro/nano manufacturing field, with the shrinking feature scale, processing is facing great challenge. Plasma etching technology as an irreplaceable tool has been widely used instead of traditional wet etching, which has the advantages of high etching rates, high selectivity and high anisotropy, it's also a key method to transfer the lithography graphics from photoresist mask to substrate. For example, fluorocarbon plasma is used to etch SiO2, while chlorine plasma is used to etch Si. The most important thing is to make sure the etching uniform, anisotropic and low radiation damage more than improving etching rates. Moreover argon is padded to enhance the ion bombardment, however ion energy and angular distribution(IED and IAD) are the key factors to directly affect the etching results, the effects of ion density on etching selectivity, charge accumulation and the influences of IEAD on surface reaction make knowing the etching mechanism hard, to accurately modulate ion density, IED and IAD during plasma etching processes is a vital issue to be reckoned with.In this masteral dissertation, one model coupled reactor model and sheath model was established. The numerical method was employed to simulate the planar-type inductively coupled plasma(ICP) discharge processes. Under the conditions of different pulsed bias waveforms and discharge parameters, researches and analysis will be done about IED and IAD arriving at the underlying substrates. The ions and neutral particles density distributions are obtained using one commercial software named CFD-ACE+ corresponding to different reaction coefficients. The ion density at sheath boundary is used as the sheath boundary condition in sheath model to get the IED and IAD. The sheath model consists of fluid model and Monte-Carlo Simulations(MCS). For Ar/C4F8 plasma discharges, the source bias is a continuous radio frequency(RF) source, and the Ar/Cl2 plasma discharge is driven by a pulsed-RF source. A tailed substrate pulsed-bias is applied on the processing substrate, which can not only effectively modulate IED and IAD but also can overcome the charging effect that count against the etching morphology.In chapter 3, we mainly discuss the IED and IAD of 6 species under the condition of different pulsed biases and discharge parameters in Ar/C4F8 plasmas. The results show that different pulsed bias waveforms and discharge parameters have a certain effect on the evolution of IED and IAD. We can get more desired IED and IAD on the basis of designing the pulsed bias waveform. In chapter 4, during the pulsed Ar/Cl2 discharge processes three kinds of ions density chamber distributions are considered under different discharge parameters, and the evolvement of IED and IAD are discussed driven by different electrode bias waveforms and parameters. The results show that high source bias duty ratio, high discharge pressure, high Ar/Cl2 inlet gas ratio can make ion density in the ICP chamber greater. Ar+ density is more than two times than Cl2+ density. IED and IAD can be modulated by the tailed substrate pulsed bias waveforms and discharges parameters.