High Selectivity in Dry Etching of Silicon Nitride over Si Using a Novel Hydrofluorocarbon Etch Gas in a Microwave Excited Plasma for FinFET

Nakao, Yukihisa; Matsuo, Tadayuki; Teramoto, Akinobu; Utsumi, H.; Hashimoto, Kazuhito; Kuroda, Rihito; Shirai, Yoshihito; Sugawa, Shigetoshi; Ohmi, Tadahiro

doi:10.1149/06103.0029ecst

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…For CH 3 F, the etching of poly-Si and SiO 2 were suppressed by introducing a small amount of O 2 (4 sccm~12sccm). In contrast the developed gas, those etching are suppressed by deposition a film on poly-Si and SiO 2 , therefore the developed gas achieve high selectivity etching (16). Furthermore, in the conditions of each etchant gas resulted in the maximum selectivity, the etch rates for the each gas were almost the same: the etch rate for the developed gas was 57 nm/min and for CH 3 F was 55 nm/min, respectively.…”

Section: Etching Characteristicsmentioning

confidence: 94%

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Introduction of a High Selectivity Etching Process with Advanced SiN_x Etch Gas in the Fabrication of FinFET Structures

et al. 2016

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We evaluated the etching characteristics of a developed prototype hydrofluorocarbon-based SiNx etch gas. The developed gas has higher etching selectivity to poly-Si and SiO2 than conventional SiNx etch gases and a maximum selectivity of 62 to poly-Si and of over 100 to SiO2 were obtained. These highly selective etching chemicals are required for the development of three-dimensional Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). In this work, we focused on Fin Field Effect Transistors (FinFETs), and in particular, FinFET structures that were fabricated by application of the developed gas to the gate spacer etch process. The FinFET structure fabricated with the developed gas is superior to that of the structure fabricated with CH3F, which is conventionally used for SiNx etching. We found that the developed gas is a promising etching gas for future high selectivity etching technologies.

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Section: Etching Characteristicsmentioning

confidence: 94%

“…Therefore, the developed gas exhibits a markedly higher etching selectivity. The deposited film can also be removed by the subsequent O 2 plasma ashing process (16). The SiN x etch rate increased with the chamber pressure decreasing.…”

Section: Etching Characteristicsmentioning

confidence: 99%

Introduction of a High Selectivity Etching Process with Advanced SiN_x Etch Gas in the Fabrication of FinFET Structures

et al. 2016

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Influence of the hard masks profiles on formation of nanometer Si scalloped fins arrays

Zhang

Wei

et al. 2018

Microelectronic Engineering

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Influence of hydrogen in silicon nitride films on the surface reactions during hydrofluorocarbon plasma etching

Kuboi¹,

Tatsumi²,

Minari³

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The influence of the amount of hydrogen (H) in hydrogenated silicon nitride films (SixNy:Hz) on the etching properties and etching mechanism are unclear for hydrofluorocarbon plasma etching. Therefore, the authors have investigated the effect of H in SixNy:Hz films on the surface reactions during CH2F2/Ar/O2 plasma etching by experimental and numerical simulation techniques. The experimental etch yield (EY) and polymer layer thickness (TC−F) values for SixNy:Hz films with different H concentrations of 2.6% (low-SiN), 16.8% (mod-SiN), and 21.9% (high-SiN) show different trends with the CH2F2/(CH2F2 + O2) flow rate ratio. To understand the mechanism of the different etching properties, the authors estimated the chemical reaction probabilities of the H outflux between F, O, N, C, and Si dangling bonds using first principles calculations and the results of Fourier transform infrared spectroscopy. Based on the estimated reaction probabilities, the authors modeled the surface reactions of SixNy:Hz films under the assumption that the H outflux mainly scavenges incident F radicals (the main etchant species). The authors also consider that the reaction between H and N from outfluxes decreases the desorption reactions of C2N2 and HCN, resulting in a larger TC−F value. Comparing the simulation results of the trends in the whole flow rate ratio range and the absolute values of EY and TC−F with experimental data, the surface model can successfully explain the mechanism. Furthermore, the authors demonstrated time-dependent etched profile and damage distribution for fin-type field-effect transistor SixNy:Hz side-wall etching using the three-dimensional voxel-slab model with the above surface reactions to obtain knowledge about the effect of H on the etched profile and damage distribution. The results show that the etched profile and damage distribution on the Si fin structure are very different for low-SiN and high-SiN because of the different EY and TC−F values induced by different H outfluxes. These results indicate that it is important to carefully control both the etching process and amount of H in the SixNy:Hz film to achieve high-performance advanced complementary metal oxide semiconductor devices.

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High Selectivity in Dry Etching of Silicon Nitride over Si Using a Novel Hydrofluorocarbon Etch Gas in a Microwave Excited Plasma for FinFET

Cited by 4 publications

References 8 publications

Introduction of a High Selectivity Etching Process with Advanced SiN_x Etch Gas in the Fabrication of FinFET Structures

Introduction of a High Selectivity Etching Process with Advanced SiN_x Etch Gas in the Fabrication of FinFET Structures

Influence of the hard masks profiles on formation of nanometer Si scalloped fins arrays

Influence of hydrogen in silicon nitride films on the surface reactions during hydrofluorocarbon plasma etching

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High Selectivity in Dry Etching of Silicon Nitride over Si Using a Novel Hydrofluorocarbon Etch Gas in a Microwave Excited Plasma for FinFET

Cited by 4 publications

References 8 publications

Introduction of a High Selectivity Etching Process with Advanced SiNx Etch Gas in the Fabrication of FinFET Structures

Introduction of a High Selectivity Etching Process with Advanced SiNx Etch Gas in the Fabrication of FinFET Structures

Influence of the hard masks profiles on formation of nanometer Si scalloped fins arrays

Influence of hydrogen in silicon nitride films on the surface reactions during hydrofluorocarbon plasma etching

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Product

Resources

About

Introduction of a High Selectivity Etching Process with Advanced SiN_x Etch Gas in the Fabrication of FinFET Structures

Introduction of a High Selectivity Etching Process with Advanced SiN_x Etch Gas in the Fabrication of FinFET Structures