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© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

The change in electrode impedance of semiconductor equipment due to repetitive processes is a major issue that creates process drift. In the current plasma etch chamber with a dual-frequency power system, the high-powered radio frequency (RF) source contributes to the enhancement of the plasma density, and the low-frequency bias power at the bottom electrode is adopted to enhance the injected ion energy in the plasma. The impedance control of the top electrode in dual-frequency capacity coupled plasma limits the impedance matching capability of the RF matching system because it only considers the high-frequency RF source. To control the precise impedance in dual-frequency semiconductor equipment, independent impedance control is required for each frequency. In this study, the impedance corresponding to a specific frequency was independently controlled using L (inductor) and C (capacitor). A 60 MHz stop filter and VVC were used to control 2 MHz impedance at a specific point, and a 2 MHz stop filter and VVC were used to control 60 MHz impedance. In the case of 2 MHz impedance control, the 2 MHz impedance changed from 10.9−j893 to 0.3−j62 and the 60 MHz impedance did not change. When controlling the 60 MHz impedance, the 60 MHz impedance changed from 0.33 + j26.53 to 0.2 + j190 and the 2 MHz impedance did not change. The designed LC circuits cover the impedance of 60 and 2 MHz separately and are verified by the change in the capacitance of the vacuum variable capacitors implemented in the RF impedance matching system.

Details

Title
Dual-Frequency RF Impedance Matching Circuits for Semiconductor Plasma Etch Equipment
Author
Lee, Jeongsu
First page
2074
Publication year
2021
Publication date
2021
Publisher
MDPI AG
e-ISSN
20799292
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2570780532
Copyright
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.