Effects of Etching Gases and Bias Frequency on Notching and Charging in High-Density Plasma

Tabara, Suguru

doi:10.1143/jjap.38.3753

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…However, it is also reported that BCl 3 degrades mask selectivity by generating heavy ions, such as BCl + 2 or BCl + 3 . The lack of photoresist selectivity with Cl 2 /BCl 3 chemistry requires a thick photoresist layer that results in poor lithography performance with an insufficient depth of focus [11] . Therefore, it becomes important to study the effect of ICP process parameters on the energies of the dominant ion species in the plasma and their impact on etching rate, etching profile, surface smoothness and selectivity of the etching process.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl₂/BCl₃-Based Inductively Coupled Plasma

Rawal¹,

Sehgal²,

Muralidharan³

et al. 2011

Plasma Sci. Technol.

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A study of Cl2/BCl3-based inductively coupled plasma (ICP) was conducted using thick photoresist mask for anisotropic etching of 50 µm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150 µm. Plasma etch characteristics with ICP process pressure and the percentage of BCl3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BCl3. In addition, variation of the etching yield with pressure and etching depth were also investigated.

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Section: Introductionmentioning

confidence: 99%

Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl₂/BCl₃-Based Inductively Coupled Plasma

Rawal¹,

Sehgal²,

Muralidharan³

et al. 2011

Plasma Sci. Technol.

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Deep-reactive ion etching of silicon nanowire arrays at cryogenic temperatures

Xu,

Refino,

Delvallée

et al. 2024

Applied Physics Reviews

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The pursuit of sculpting materials at increasingly smaller and deeper scales remains a persistent subject in the field of micro- and nanofabrication. Anisotropic deep-reactive ion etching of silicon at cryogenic temperatures (cryo-DRIE) was investigated for fabricating arrays of vertically aligned Si nanowires (NWs) of a large range of dimensions from micrometers down to 30 nm in diameter, combined with commonly used wafer-scale lithography techniques based on optical, electron-beam, nanoimprint, and nanosphere/colloidal masking. Large selectivity of ∼100 to 120 and almost 700 was found with resists and chromium hard masks, respectively. This remarkable selectivity enables the successful transfer of patterned geometries while preserving spatial resolution to a significant extent. Depending on the requirements by applications, various shapes, profiles, and aspect ratios were achieved by varying process parameters synchronously or asynchronously. High aspect ratios of up to 100 comparable to the best result by metal-assisted wet-chemical etching and sub-μm trenches by DRIE were obtained with NW diameter of 200 nm, at an etch rate of ∼4 μm/min without being collapsed. At the same time, low surface roughness values were maintained on the NW top, sidewall, and bottom surface of ∼0.3, ∼13, and ∼2 nm, respectively, as well as high pattern fidelity and integrity, which were measured using angle-resolved Fourier microscopy, combined atomic force, and scanning electron microscopy on selected NWs. This work establishes the foundation in the controllable development of Si nanoarchitectures, especially at sub-100 nm structures, for energy-harvesting and storage, damage-free optoelectronics, quantum, photovoltaics, and biomedical devices.

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Critical tasks in high aspect ratio silicon dry etching for microelectromechanical systems

Rangelow¹

2003

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

178

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The process of pattern transfer of desired topological features into silicon plays a critical role for the production of microelectronic and photonic devices, and micro- and nanoelectromechanical systems. Any deviation from the desired shape of the pattern limits density, yield, and reliability of these devices. Gas reactivity, pressure, ion, electron, and reactant transport to the surface, and product transport away from the surface, have all been identified as important issues that control the microscopic uniformity in high aspect ratio etching. When etch-inhibiting chemistry by the gas chopping deep reactive ion etching (RIE) was employed, it caused enormous complications in the scaling of etching rates, with increasing aspect ratio. Using an energy-resolving quadrupole mass spectrometer assembled into the cathode, specially designed test features, and etching simulation models, we establish the link between etch process parameters such as pressure, rf power, etching gas chemistry, temperature, and the physical and chemical process parameters like energy and angular distribution of ions and neutrals, radical sticking, and surface charging. The most significant effects like RIE lag, notching, bowing, faceting, microtrenching, profile shape dependence, etc. will be discussed in this article. 2003 American Vacuum Society.

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Effects of Etching Gases and Bias Frequency on Notching and Charging in High-Density Plasma

Cited by 4 publications

References 18 publications

Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl₂/BCl₃-Based Inductively Coupled Plasma

Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl₂/BCl₃-Based Inductively Coupled Plasma

Deep-reactive ion etching of silicon nanowire arrays at cryogenic temperatures

Critical tasks in high aspect ratio silicon dry etching for microelectromechanical systems

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Effects of Etching Gases and Bias Frequency on Notching and Charging in High-Density Plasma

Cited by 4 publications

References 18 publications

Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl2/BCl3-Based Inductively Coupled Plasma

Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl2/BCl3-Based Inductively Coupled Plasma

Deep-reactive ion etching of silicon nanowire arrays at cryogenic temperatures

Critical tasks in high aspect ratio silicon dry etching for microelectromechanical systems

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Product

Resources

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Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl₂/BCl₃-Based Inductively Coupled Plasma

Experimental Study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl₂/BCl₃-Based Inductively Coupled Plasma