Suppression of Microloading Effect by Low-Temperature SiO<sub>2</sub> Etching

Sato, Masayuki; Takehara, Daisuke; Uda, Keichiro; Sakiyama, K.; Hara, Tohru

doi:10.1143/jjap.31.4370

Cited by 10 publications

(8 citation statements)

References 3 publications

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“…It was expected that lowering the substrate temperature would change the surface reaction rates and thereby reduce the aspect ratio dependence of the etch rates. [20][21][22][23] However, the etch rates plotted in Fig. 7 still show an aspect ratio dependence as well as an apparent dependence on trench width.…”

Section: Ion-neutral Synergy Model With Etch Inhibition: Treatmentmentioning

confidence: 91%

“…5,6,17,18,20,23,24 Since there are many ways to analyze the data, the lack of information confounds comparisons between data from different studies. Commonly, average etch rate data obtained for a single etch time is plotted as a function of feature width 5,6,20,23,24,34 despite strong evidence that the etch rate is a function of aspect ratio alone. Such scaling cannot be deduced without measuring etch rates as a function of time as well as width.…”

Section: Experimental Procedures and Data Analysismentioning

confidence: 99%

“…20,21,23 To account for such an effect, we extend the model above by considering the deposition of an etch inhibiting layer which competes with reactant for the same surface sites and which follows the same Langmuir adsorption kinetics.…”

Section: Ion-neutral Synergy Model With Etch Inhibition: Treatmentmentioning

confidence: 99%

“…1 Physical phenomena that can play a role in etch rate nonuniformity include deposition of etch inhibitors, 20,[23][24][25] ion shadowing, 5,6,9,18 ion deflection, 19,26 -30 neutral shadowing, 18 Knudsen transport of neutrals, 31 surface diffusion, 24 and bulk diffusion. 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.…”

Section: Introductionmentioning

confidence: 99%

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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: Ion-neutral Synergy Model With Etch Inhibition: Treatmentmentioning

confidence: 91%

Section: Experimental Procedures and Data Analysismentioning

confidence: 99%

Section: Ion-neutral Synergy Model With Etch Inhibition: Treatmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

View full text Add to dashboard Cite

show abstract

“…Up to now, many researchers have been studying this subject. 3,[8][9][10][11][12][13] In RIE, the etching reaction is promoted by high-energy ions irradiating to low-molecular-weight fluorocarbon gases (fluorocarbon radicals generated by dissociation of fluorocarbon gas) adsorbed on the substrate surface. 1,2,14,15) Therefore, one factor that determines the etching characteristics is the adsorption behavior of low-molecular-weight fluorocarbon gases on the substrate surface.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Behavior of Various Fluorocarbon Gases on Silicon Wafer Surface

Hidaka

Yamashita

Ishii

et al. 2005

Jpn. J. Appl. Phys.

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An analytical technique to clarifying the adsorption behavior of a fluorocarbon gas, which is one of the key steps in reactive ion etching, has been established. In this paper, we focus on the adsorption behavior of fluorocarbon gases to the silicon wafer surface to clarify the etching mechanism in order to realize etching to a high aspect ratio. Each fluorocarbon gas had surface selectivity for SiO2, Si and the photoresist. Each fluorocarbon gas reacted differently at the silicon wafer surface. As a result, the etching mechanism could be clarified using this newly established analytical technique. Therefore, an etching mechanism will be able to be clarified by applying the newly established analytical technique to the fluorocarbon gases expected to be useful for etching of high aspect ratio and further high performance ultra large scale integrated circuit device must be realized.

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