Evaluation of plasma charging damage during polysilicon gate etching process in a decoupled plasma source reactor

Ma, Shawming; Jain, Mohit; Chinn, Jeff

doi:10.1116/1.581165

Cited by 35 publications

(6 citation statements)

References 7 publications

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“…Recent advancements in plasma processing for the gate electrode, sidewall, and high-aspect (more than 10) contact hole have highlighted the importance of fully understanding how the plasma induces damage and how to control this damage. The damage is classified on the basis of its mechanism as charging damage, [1][2][3][4] physical damage, [5][6][7][8][9][10][11][12] and ultraviolet/ vacuum-ultraviolet (UV/VUV) radiation damage [13][14][15][16] during plasma etching. Physical damage to the Si, SiO 2 , and Si 3 N 4 layers, which is considered to be caused by ion bombardment, has been the particular focus of extensive research.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO₂ Etching

Kuboi¹,

Tatsumi²,

Kobayashi³

et al. 2011

Jpn. J. Appl. Phys.

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We developed a numerical simulation method for the depth profiles of plasma-induced physical damage to SiO2 and Si layers during fluorocarbon plasma etching. In the proposed method, the surface layer is assumed to consist of two layers: a C–F polymer layer and a reactive layer. Physical and chemical reactions in the reactive layer divided into several thin slabs and in the deposited C–F polymer layer, which depend on etching parameters, such as etching time, gas flow rate, gas pressure, and ion energy (V pp), are considered in detail. We used our simulation method to calculate the SiO2 etch rate, the thickness of the C–F polymer layer (T C–F), and the selectivity of SiO2 to Si during C4F8/O2/Ar plasma etching. We confirmed that the calculated absolute values and their behavior are consistent with experimental data. We also successfully predicted depth profiles of physical damage to the Si and SiO2 layers introducing our re-gridding method. We found that much Si damage is generated in the pre- and early stages of the overetching step of SiO2/Si layer etching despite the high selectivity. These simulation results suggest that the T C–F value and the overetching time must be carefully controlled by process parameters to reduce damage during fluorocarbon plasma etching. The results have also provided us with useful knowledge for controlling the etching process.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO₂ Etching

Kuboi¹,

Tatsumi²,

Kobayashi³

et al. 2011

Jpn. J. Appl. Phys.

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“…Therefore if a high efficiency of oxidization power is obtained on SWP plasma equipments, it is possible to make a high quality TEOS oxide film such as RLSA TEOS. However a high density decoupled plasma 16) or an electron cyclotron resonance 17) even they might be able to make a high efficiency of oxidization power, PID might cause the degradation of the SiO 2 quality.…”

Section: Discussionmentioning

confidence: 99%

High-Quality SiO₂Film Formation below 400 °C by Plasma Enhanced Chemical Vapor Deposition Using Tetraethoxysilane Source Gas

Ueda

Ohsawa

Tanaka

et al. 2009

Jpn. J. Appl. Phys.

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The plasma enhanced chemical vapor deposition (PECVD) of extremely high-quality SiO2 at low temperature below 400 °C has been developed using tetraethoxysilane (TEOS). Plasma of TEOS and Ar, O2 gases was generated by a microwave (2.45 GHz) radial-line-slot-antenna (RLSA) system. The RLSA Plasma is a sort of surface-wave-plasma (SWP) and it realizes lower electron temperature (Te) with higher electron density (Ne) at the wafer position compared with conventional PECVD reactors. The physical properties were examined by 5% HF wet etching rates and thermal desorption spectroscopy. It was confirmed that the RLSA TEOS film were much better than conventional PECVD films and a high temperature oxide (HTO) with 900 °C N2 anneal treatment. Electrical properties of dielectric leakage, breakdown and negative bias charge-to-breakdown (Qbd) test also performed. The RLSA TEOS films showed far better properties among the conventional films and in much the same quality as a wet-thermal oxide grown at 950 °C. It was considered that all these properties were owing to the RLSA plasma's uniqueness of lower plasma damage and oxidization efficiency for precursors.

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“…Etching experiments are performed in a Tokyo Electron Limited DRM TM chamber for the etching of the dielectrics layers (SiO 2 and SiOCH) and in an Applied Materials DPS TM chamber for the etching of the TiN hard mask. The schematics of the DRM TM and DPS TM reactors have been previously described elsewhere [9,10]. The etching platform, on which the DPS TM chamber is mounted, is connected to an X-ray photoelectron spectroscopy (XPS) surface analysis system (customized 220I system from VG scientific) via a transfer chamber.…”

Section: Methodsmentioning

confidence: 99%

Patterning of narrow porous SiOCH trenches using a TiN hard mask

Darnon

Chevolleau

Eon

et al. 2008

Microelectronic Engineering

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For the next technological generations of integrated circuits, the traditional challenges faced by etch plasmas (profile control, selectivity, critical dimensions, uniformity, defects, ...) become more and more difficult, intensified by the use of new materials, the limitations of lithography, and the recent introduction of new device structures and integration schemes. Particularly in the field of the interconnect fabrication, where dual-damascene patterning is performed by etching trenches and vias in porous low-k dielectrics, the main challenges are in controlling the profile of the etched structures, minimizing plasma-induced damage, and controlling the impact of various types of etch stops and hard mask materials. Metallic hard masks can help thanks to their high selectivity toward low-k materials, and by avoiding low-k exposure to potentially degrading ashing plasmas. In this paper, we will present some key issues related to the patterning of narrow porous SiOCH trenches with a metallic (TiN) hard mask. Narrow trenches (down to 40 nm width) can be opened into TiN with a critical dimensions bias (around 10 nm) attributed to carbon and silicon containing deposits on the photoresist and TiN sidewalls during the etching. Porous SiOCH etching using a TiN hard mask instead of the conventional SiO 2 hard mask may lead to severe profile distortions, attributed to TiF x compounds which settle on the trenches sidewalls. A chuck temperature of 60°C and fluorine-rich plasmas are required to minimize those distortions. An etching process leading to almost straight porous SiOCH profiles presenting a slight bow has been developed. However a wiggling phenomenon has been evidenced for the etching of narrow and deep trenches. This phenomenon is attributed to the highly compressive residual stress in the TiN hard mask, which is released when the dielectric is not mechanically strong enough to withstand it.

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Evaluation of plasma charging damage during polysilicon gate etching process in a decoupled plasma source reactor

Cited by 35 publications

References 7 publications

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO₂ Etching

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO₂ Etching

High-Quality SiO₂Film Formation below 400 °C by Plasma Enhanced Chemical Vapor Deposition Using Tetraethoxysilane Source Gas

Patterning of narrow porous SiOCH trenches using a TiN hard mask

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Evaluation of plasma charging damage during polysilicon gate etching process in a decoupled plasma source reactor

Cited by 35 publications

References 7 publications

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO2 Etching

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO2 Etching

High-Quality SiO2Film Formation below 400 °C by Plasma Enhanced Chemical Vapor Deposition Using Tetraethoxysilane Source Gas

Patterning of narrow porous SiOCH trenches using a TiN hard mask

Contact Info

Product

Resources

About

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO₂ Etching

Numerical Simulation Method for Plasma-Induced Damage Profile in SiO₂ Etching

High-Quality SiO₂Film Formation below 400 °C by Plasma Enhanced Chemical Vapor Deposition Using Tetraethoxysilane Source Gas