Spatial profiles of interelectrode electron density in direct current superposed dual-frequency capacitively coupled plasmas

Effects of applying a high negative direct current (dc) voltage in argon capacitive coupled plasmas on the flux of secondary electrons (SEs) to a radiofrequency (rf) biased electrode and plasma uniformity were investigated using particle-in-cell Monte Carlo collision simulation and results were compared with experimental results. High energy SEs originating at electrodes with high negative dc voltage due to ion-impact as well as electron-impact were accelerated out of the sheath through the sheath voltage drop. These SEs gain energy equal to the applied dc voltage and either travel to the wafer electrode where they are lost (dumped) or are trapped between electrodes depending on the voltage on bottom electrode. Trapping and dumping of ballistic electrons depends on the magnitudes of the voltages (dc and rf) applied to each electrode. High energy SEs alter the electron energy distribution function at the wafer, high energy electron flux to the wafer and the plasma density profile. With the application of negative dc voltage, wafer receives high energy electron flux with energies up to applied dc voltage. For the range of conditions examined in this paper, the plasma density increases with the application of the negative dc voltage due to ionization by trapping of high energy SEs. The electrons that originate at the negative dc electrode minimize the impact of enhanced radial electric fields at the rf electrode edge allowing dc/rf plasmas to be center peaked even at low (13.56 MHz) rf frequencies.

Section: Discussionmentioning

confidence: 99%

Simulations of hybrid direct current radiofrequency (dc/rf) capacitively coupled plasmas

Ranjan¹,

Ventzek²

2019

“…38) The spatial distribution of plasma density in a chamber was revealed by the cutoff probe 39,40) and the surface-wave probe. 41,42) Optical diagnostics are categorized into passive and active methodologies. The former is optical emission spectroscopy (OES), in which plasma, as a measurement target, is emitted as a light source.…”

Section: 5mentioning

confidence: 99%

Science-based, data-driven developments in plasma processing for material synthesis and device-integration technologies

Kambara

Kawaguchi

Lee

et al. 2022

Self Cite

Low-temperature plasma processing technologies is essential for material synthesis, device fabrication, and surface treatment. The development of plasma-related products and services requires an understanding of the multiscale complex behaviors of plasma and the hierarchical integration of plasma generation, energy and mass transports through sheath region, surface reactions, and other processes. The importance of science-based and data-driven approaches to controlling systems is argued. The state-of-the-art of deep learning, machine learning, and artificial intelligence in low-temperature plasma science and technology is reviewed. In this review, the requirements and challenges for plasma parameter prediction and processing recipe discovery are asserted by researchers in the fields of material science and plasma processing. It also outlined a science-based, data-driven approach for development of virtual metrology in plasma processes.

“…Recently, the control settings of plasma equipment to achieve optimal charge transport have been debated, with some arguing for the synchronous application of bias power or a direct current (dc) bias. [37][38][39] For instance, Tokashiki et al reported that the adoption of synchronous pulse plasma etching technology improved the CD uniformity for large-diameter wafers owing to control of the ion flux and energy as well as radical-to-ion flux ratios. 40) In addition to charged particle transport, the wafer temperature plays an important role in the control of etched feature profiles and CD uniformity.…”

Section: Har Feature Profile Control: From Two Dimensions To Three Di...mentioning

confidence: 99%

Progress in nanoscale dry processes for fabrication of high-aspect-ratio features: How can we control critical dimension uniformity at the bottom?

Ishikawa

Karahashi

Ishijima

et al. 2018

Self Cite

In this review, we discuss the progress of emerging dry processes for nanoscale fabrication of high-aspect-ratio features, including emerging design technology for manufacturability. Experts in the fields of plasma processing have contributed to addressing the increasingly challenging demands of nanoscale deposition and etching technologies for high-aspect-ratio features. The discussion of our atomic-scale understanding of physicochemical reactions involving ion bombardment and neutral transport presents the major challenges shared across the plasma science and technology community. Focus is placed on advances in fabrication technology that control surface reactions on three-dimensional features, as well as state-of-the-art techniques used in semiconductor manufacturing with a brief summary of future challenges.