Effects of ion energy distribution on topography dependent charging

Ma, Shawming; Hane, M.; McVittie, J.P.

doi:10.1109/vlsit.1996.507847

Cited by 4 publications

(3 citation statements)

References 4 publications

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“…Figure 6͑b͒ shows the ion energy distribution function ͑IEDF͒ calculated using the Monte Carlo simulation. 9 Highenergy IEDF peaks at bias powers of 400, 800, and 1500 W were observed at about 780, 1230, and 1840 eV, respectively. The C-F polymer on the etched surface decelerated the ion energy during etching, showing that the amount of energy loss, ⌬V, depends on T C-F .…”

Section: A Balance Pointmentioning

confidence: 94%

Control of atomic layer degradation on Si substrate

Nakamura¹,

Tatsumi²,

Kobayashi³

et al. 2007

Journal of Vacuum Science & Technology A: Vacuum, Surfaces,

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To develop 32 nm node devices, the degradation of atomic layers on the surface of Si substrates must be controlled. During the etching of a SiO 2 or Si 3 N 4 hard mask or sidewall, the surface of Si is attended due to exposure to fluorocarbon plasma. The authors have quantitatively evaluated the relationship between the energy of incident ions and the thickness of the fluorocarbon polymer for a CH 2 F 2 /CF 4 /Ar/O 2 plasma in a dual frequency CCP system. At a fixed ion energy the thickness of the damage layer ͑T d ͒ basically depended on the thickness of the fluorocarbon polymer ͑T C-F ͒. When the T C-F was changed by controlling the O / CF x gas ratio, T d had a minimum thickness under the conditions at balance point: P b , under which the T C-F was nearly equal to ion penetration depth: D p. Using molecular dynamics simulation, reaction around the transition from SiO 2 to Si was clarified. The damage was done to the Si before the SiO 2 was completely removed, and the largest T d was observed when the SiO 2 was etched off. After that, T C-F began to increase because there was no longer an outflux of O from SiO 2 and the damage decreased as the unstable SiF x species in the damaged layer desorbed. Once the T C-F became thicker than the ion penetration depth, the damaged layer got buried and T d stopped changing. When the ion penetration depth was controlled to be equal to T C-F in a steady state under low ion energy conditions, the T d was reduced to less than 1 nm.

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Section: A Balance Pointmentioning

confidence: 94%

Control of atomic layer degradation on Si substrate

Nakamura¹,

Tatsumi²,

Kobayashi³

et al. 2007

Journal of Vacuum Science & Technology A: Vacuum, Surfaces,

View full text Add to dashboard Cite

show abstract

“…As mentioned above, the measured peak-to-peak voltage was used as a function of pressure to estimate the minimum energy of the ions bombarding the substrate, which is a function of ion mass, electron mass, electron temperature and peak-to-peak voltage at the substrate [20] . Table 1 lists the calculated minimum ion energy at the substrate for all possible species of ions.…”

Section: Minimum Ion Energy Variation With Process Pressurementioning

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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“…Moreover, narrowing IEDF increases charging potential and therefore, enhances side etching in gate Si etching. 10,11) Hence, the suppression of local charging should be investigated to reduce the amount of side etching at a high-frequency bias. In reducing charging potential, leakage current along the surface of etched patterns is a key factor.…”

Section: Introductionmentioning

confidence: 99%

Negative Impact of Etched Si Area on Selectivity and Positive Impact of Photoelectric Current on Etched Profile in Gate Etching with Different Wafer Bias Frequencies

Kamibayashi¹,

Kofuji²,

Mori³

et al. 2013

Jpn. J. Appl. Phys.

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The effect of wafer-bias frequency on the dummy-gate fabrication of fin-shaped field-effect transistor (Fin-FET) was investigated. The clear difference in the selectivity of polycrystalline silicon to SiO2 between 400 kHz and 13.56 MHz decreased when the etched Si area increased. On the other hand, a higher frequency increased such selectivity when Si area decreased. These results can be explained by the effect of by-product deposition. As for the etched profile, the amount of side etching was much larger at 13.56 MHz than at 400 kHz. It was reported that this phenomenon is caused by local charging. It was also suggested that the charging should be suppressed by reducing the ratio of ion saturation current to photoelectric current. Therefore, in this study, we investigated the effect of such current ratio on side etching. The result confirmed that a reduction in current ratio induced by increasing gas pressure decreases the amount of side etching.

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Effects of ion energy distribution on topography dependent charging

Cited by 4 publications

References 4 publications

Control of atomic layer degradation on Si substrate

Control of atomic layer degradation on Si substrate

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

Negative Impact of Etched Si Area on Selectivity and Positive Impact of Photoelectric Current on Etched Profile in Gate Etching with Different Wafer Bias Frequencies

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Effects of ion energy distribution on topography dependent charging

Cited by 4 publications

References 4 publications

Control of atomic layer degradation on Si substrate

Control of atomic layer degradation on Si substrate

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

Negative Impact of Etched Si Area on Selectivity and Positive Impact of Photoelectric Current on Etched Profile in Gate Etching with Different Wafer Bias Frequencies

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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