Advances in Langmuir probe diagnostics of the plasma potential and electron-energy distribution function in magnetized plasma

Popov, Tsv K; Dimitrova, M.; Ivanova, P. K.; Kovačič, J.; Gyergyek, T.; Dejarnac, R.; Ştöckel, J.; Pedrosa, M. A.; López‐Bruna, D.; Hidalgo, C.

doi:10.1088/0963-0252/25/3/033001

Cited by 62 publications

(59 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More details about the chamber can be found elsewhere. [19][20][21][22][23] A commercial Langmuir probe [24][25][26][27][28][29] (Impedans ALP System TM ) is used to measure the electron density at the axial center and 3 cm below the quartz window. The probe tip is made of tungsten wire with 10 mm in the length and 0.3 mm in the diameter.…”

Section: Methodsmentioning

confidence: 99%

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O₂ plasma*

Gao

Wang

et al. 2021

Chinese Phys. B

View full text Add to dashboard Cite

This paper presents the evolution of the electronegativity with the applied power during the E to H mode transition in a radio frequency (rf) inductively coupled plasma (ICP) in a mixture of Ar and O2. The densities of the negative ion and the electron, as well as their ratio, i.e., the electronegativity, are measured as a function of the applied power by laser photo-detachment combined with a microwave resonance probe, under different pressures and O2 contents. Meanwhile, the optical emission intensities at Ar 750.4 nm and O 844.6 nm are monitored via a spectrograph. It was found that by increasing the applied power, the electron density and the optical emission intensity show a similar trench, i.e., they increase abruptly at a threshold power, suggesting that the E to H mode transition occurs. With the increase of the pressure, the negative ion density presents opposite trends in the E-mode and the H-mode, which is related to the difference of the electron density and energy for the two modes. The emission intensities of Ar 750.4 nm and O 844.6 nm monotonously decrease with increasing the pressure or the O2 content, indicating that the density of high-energy electrons, which can excite atoms, is monotonically decreased. This leads to an increase of the negative ion density in the H-mode with increasing the pressure. Besides, as the applied power is increased, the electronegativity shows an abrupt drop during the E- to H-mode transition.

show abstract

Section: Methodsmentioning

confidence: 99%

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O₂ plasma*

Gao

Wang

et al. 2021

Chinese Phys. B

View full text Add to dashboard Cite

show abstract

“…Several authors worked on this subject (Langmuir, [ 15 ] Bohm, [ 13 ] Laframboise, [ 31,49 ] Chen, [ 50 ] etc. [ 10,11,51–53 ] ). A global overview on major theories is available herein.…”

Section: Experimental Designmentioning

confidence: 99%

Experimental and theoretical study of density, potential, and current structures of a helium plasma in front of an radio frequency antenna tilted with respect to the magnetic field lines

Ledig

Faudot

Moritz

et al. 2020

Contributions to Plasma Physics

View full text Add to dashboard Cite

Potential and density structures in the vicinity of a RF electrode/antenna in a magnetized plasma are investigated using a RF compensated cylindrical Langmuir probe. These measurements were performed in the ALINE plasma device in which only electrons can be considered as well magnetized. Very precise 2-D maps of the plasma parameters are drawn thanks to a 3-D automatic manipulator on which the probe is mounted. The effect of the tilted magnetic angle between the RF biased surface and the magnetic lines is also studied thanks to a tilting electrode. Comparison of several simplistic models with the experiments proved the reliability of simple Langmuir probe measurements in such a RF and magnetized environment (space potential v.s. tilting angle of the antenna with respect to magnetic field lines, and recovering of the floating potential structure using measured currents). A fluid model based on total current density, and ion diffusion equations over the biased flux tube, provides the same density structures in front of the electrode than the measurements. Those density structures display a "bunny ears" shape, and can be explained using transverse RF and collisional current behaviour: in front of the antenna the transverse ion currents deplete the magnetized flux tube, while at the edge of the biased flux tube, the same currents rise the density. 36 probes can be used to get the plasma's main pa-37 rameters, and probe measurements are technically 38 speaking relatively easy to perform. There is al-39 ready a large documentation on this subject 10-16 40 especially in a steady and non magnetized plasma 41 where a Langmuir probe measurement can provide 42 a robust estimation of the whole bulk plasma den-43 sity, temperature and potentials (floating V fl and 44 plasma φ p ones). 45 But the problem is more challenging when 46 performing these measurements in a magnetized 47 plasma 17-23 and even more when connected to a 48 radio-frequency (RF) antenna/electrode 24-30. In-49 deed, turning on the magnetic field breaks down 50 isotropy and the probe measurement is then only 51 defined locally (measured parameters can drasti-52 cally change when moving across magnetic field 53 lines). It is then needed to perform measurements 54 into several areas of the plasma in order to access 55 to the full structure of plasma parameters. But the 56 most difficult issue is to understand how the current 57 is collected by a cylindrical probe when it is aligned 58 with magnetic field. This topic has been addressed 59 by several authors in the case of strongly magne-60 tized electrons 22,31. But in the case of weakly mag-61 netized ions, such as in small plasma discharges, 62 the ion part in the I(V) characteristics remains the 63 best way to deduce the plasma density, particularly 64 in RF environment because ions are less sensitive 65 to RF oscillations 24. On the electrons part of the 66 characteristics, cylindrical probes exhibits a strong 67 157 trode inclination, and that the ion larmor radius is of 158 the order of 400 µm at 94 mT). ...

show abstract

“…The state of a plasma can be defined as the electron temperature and plasma density 4,5 . However, these state values do not always guarantee the same result even if the given input variable is the same.…”

Section: Introductionmentioning

confidence: 99%

Virtual metrology scheme for predictive plasma uniformity diagnosis of plasma-enhanced atomic layer deposition process using optical emission spectroscopy

Kim

Na²,

Yun³

2023

Photonic Instrumentation Engineering X

View full text Add to dashboard Cite

Plasma is widely used in etching, deposition, ashing, and ion implantation processes in the manufacturing processes of semiconductor and display devices. Recently, the role of plasma in semiconductor processes is becoming important because the pattern with high step coverage and aspect ratio is required as the semiconductor process is scaled. In particular, plasma-enhanced atomic layer deposition (PE-ALD) is recently highlighted with excellent deposition uniformity compared to chemical vapor deposition (CVD) and physical vapor deposition (PVD) technologies 1 . The density and the state of plasma during the process cannot always remain constant and can be changed by process variables and unpredictable process random fluctuations. Since this can cause yield drop and decrease in productivity, the methodology for monitoring and diagnosing the abnormality of plasma in real time during the process is essentially required.In this paper, the plasma monitoring using the optical emission spectroscopy (OES) in PE-ALD equipment to analyze the characteristics of the process variables. Based on the diagnosis results, the optimal process variable values were proposed, and a process performance predictive model is introduced by analyzing the correlation between variables. Based on the modeling results, the modeling output for the final deposited thickness can be predicted by the initial deposition rate, which can be developed as a virtual metrology system application. In addition, by applying this proposed virtual metrology scheme for the advanced process control (APC), it is possible to estimate the process output without whole wafer measuring, thereby improving the time and cost losses and the wafer-to-wafer variation in the semiconductor manufacturing industry.

show abstract

Advances in Langmuir probe diagnostics of the plasma potential and electron-energy distribution function in magnetized plasma

Cited by 62 publications

References 49 publications

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O₂ plasma*

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O₂ plasma*

Experimental and theoretical study of density, potential, and current structures of a helium plasma in front of an radio frequency antenna tilted with respect to the magnetic field lines

Virtual metrology scheme for predictive plasma uniformity diagnosis of plasma-enhanced atomic layer deposition process using optical emission spectroscopy

Contact Info

Product

Resources

About

Advances in Langmuir probe diagnostics of the plasma potential and electron-energy distribution function in magnetized plasma

Cited by 62 publications

References 49 publications

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O2 plasma*

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O2 plasma*

Experimental and theoretical study of density, potential, and current structures of a helium plasma in front of an radio frequency antenna tilted with respect to the magnetic field lines

Virtual metrology scheme for predictive plasma uniformity diagnosis of plasma-enhanced atomic layer deposition process using optical emission spectroscopy

Contact Info

Product

Resources

About

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O₂ plasma*

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O₂ plasma*