Simulation of reactive ion etching pattern transfer

Shaqfeh, Eric S. G.; Jurgensen, Charles W.

doi:10.1063/1.343823

Cited by 110 publications

(53 citation statements)

References 9 publications

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“…1 The fact that many of these mechanisms may be important to varying degrees in every plasma etching situation has been repeatedly shown in profile simulations. 11,[32][33][34] The plethora of possible mechanisms is also evident in the difficulty process engineers have in determining optimum etch conditions for next generation design rules.…”

Section: Introductionmentioning

confidence: 99%

Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Bailey

Sanden

Gregus

et al. 1995

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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The scaling of etch rates with feature dimensions is an important issue in the fabrication of microelectronic and photonic devices. Because etch rates depend on circuit layouts and design rules, considerable effort is spent to modify processes each time changes in design are made. Knowing how etch rates scale with design parameters should accelerate the introduction of new designs into manufacturing while minimizing the cost of doing so. Recently it has been shown that etch rates for a variety of conditions scale with the depth/width or aspect ratio and not on width or depth alone. While various mechanisms might be responsible for such scaling, isolating one mechanism from another is not straight forward. Nonetheless, it is important to understand the underlying mechanisms so that differences in etch chemistry and etch reactor design can be accounted for when scaling plasma processes from one design or reactor to another. To assess the effects of etch chemistry alone, the trench etch rates of Si and GaAs are compared under constant plasma conditions. Substrate temperature is varied to further assess the relative importance of surface vs transport phenomena during the etching process. At higher temperatures, both Si and GaAs trench etch rates scale only with aspect ratio in an Ar/Cl2 electron cyclotron resonance plasma. The results are consistent with an ion-neutral synergy model based on Langmuir adsorption kinetics where the scaling can be explained by the aspect ratio dependence of the neutral reactant transport into the trench: charging effects, ion shadowing, and Knudsen transport are not consistent with the data. At −45 °C, the etch rate no longer scales with aspect ratio alone, but now also depends on trench width. The data at this lower temperature are well described by a model incorporating the deposition of an etch inhibiting layer. While the trench etch rates for GaAs and Si scale in similar ways with aspect ratio and trench width, the dependence on feature dimensions of the Si etch rate is much stronger than that for GaAs at all substrate temperatures because the steady-state surface coverage of Cl is smaller for Si. This results in a greater sensitivity to the incoming, aspect ratio dependent, neutral fluxes. The implications of the models on the goal of aspect ratio independent etching are also discussed.

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Section: Introductionmentioning

confidence: 99%

Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Bailey

Sanden

Gregus

et al. 1995

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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show abstract

“…Although there are many factors of RIE lag, ARDE can be explained by three main reasons: ion shadowing, neutral shadowing, differential charging. Ion shadowing means the loss of ion flux at the bottom of the etched structure [12], neutral shadowing is caused by the depleted reactive neutral species in plasma [14,15], and differential charging which describes a tendency in which the top of pattern and top of sidewall is negatively charged and the bottom surface is positively charged if aspect ratio is higher [16]. In this experiment, we postulate that ion shadowing is the main reason for the observed ARDE.…”

Section: Aspect-ratio-dependent-etching (Arde)mentioning

confidence: 82%

“…7. Silicon etch rate is retarded especially with narrower pattern sizes is known as aspect-ratio-dependentetching (ARDE) [12] or reactive ion etching (RIE) lag [13,14]. Although there are many factors of RIE lag, ARDE can be explained by three main reasons: ion shadowing, neutral shadowing, differential charging.…”

Section: Aspect-ratio-dependent-etching (Arde)mentioning

confidence: 99%

Use of Hard Mask for Finer (<10 μm) Through Silicon Vias (TSVs) Etching

Choi¹,

Hong

2015

Transactions on Electrical and Electronic Materials

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Through silicon via (TSV) technology holds the promise of chip-to-chip or chip-to-package interconnections for higher performance with reduced signal delay and power consumption. It includes high aspect ratio silicon etching, insulation liner deposition, and seamless metal filling. The desired etch profile should be straightforward, but high aspect ratio silicon etching is still a challenge. In this paper, we investigate the use of etch hard mask for finer TSVs etching to have clear definition of etched via pattern. Conventionally employed photoresist methods were initially evaluated as reference processes, and oxide and metal hard mask were investigated. We admit that pure metal mask is rarely employed in industry, but the etch result of metal mask support why hard mask are more realistic for finer TSV etching than conventional photoresist and oxide mask.

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“…[12][13][14] Depending on the ratio between the width and the depth of a structure, substantial fractions of ions may be lost by wall collisions, known as shadowing. 15 Consequently, the ion flux necessary for bottom passivation removal and ion etch assistance is decreased, ultimately limiting etch rates. This phenomenon is commonly known as the RIE-lag or aspect ratio dependent etching (ARDE).…”

Section: Introductionmentioning

confidence: 99%

Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

Stöhr

Michael-Lindhard

Hübner

et al. 2015

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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O. (2015). Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses. Journal of Vacuum Science and Technology. Part B. Microelectronics and Nanometer Structures, 33(6), [062001]. DOI: 10.1116/1.4931622 Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses This article describes the realization of complex high-aspect ratio silicon structures with feature dimensions from 100 lm to 100 nm by deep reactive ion etching using the Bosch process. As the exact shape of the sidewall profiles can be crucial for the proper functioning of a device, the authors investigated how sacrificial structures in the form of guarding walls and pillars may be utilized to facilitate accurate control of the etch profile. Unlike other sacrificial structuring approaches, no silicon-on-insulator substrates or multiple lithography steps are required. In addition, the safe removal of the sacrificial structures was accomplished by thermal oxidation and subsequent selective wet etching. The effects of the dimensions and relative placement of sacrificial walls and pillars on the etching result were determined through systematic experiments. The authors applied this process for exact sidewall control in the manufacture of x-ray lenses that are very sensitive to sidewall shape nonuniformities. Compound kinoform lenses for focusing hard x-rays with structure heights of 200 lm were manufactured, and the lenses were tested in terms of their focusing ability and refracting qualities using synchrotron radiation at a photon energy of 17 keV. A 180 lm long line focus with a waist of 430 nm at a focal length of 215 mm was obtained.

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Simulation of reactive ion etching pattern transfer

Cited by 110 publications

References 9 publications

Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Use of Hard Mask for Finer (<10 μm) Through Silicon Vias (TSVs) Etching

Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

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