Unintended gas breakdowns in narrow gaps of advanced plasma sources for semiconductor fabrication industry

• Published in: Applied physics letters 2023-12, Vol.123 (23)
• Main Authors: Son, Sung Hyun, Go, Geunwoo, Villafana, Willca, Kaganovich, Igor D, Khrabrov, Alexander, Lee, Hyo-Chang, Chung, Kyoung-Jae, Chae, Gwang-Seok, Shim, Seungbo, Na, Donghyeon, Kim, June Young
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Applied physics; Chambers; Charged particles; Discharge; Electric fields; Electrical properties and parameters; Gas breakdown; Gas discharges; Inductively coupled plasma; Particle density (concentration); Plasma processing; Plasma sheaths; Plasma sources; Semiconductors; Threshold voltage
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0172566

Occurrence of unintended gas breakdown in the narrow gaps of plasma processing chambers is one of the critical challenges in developing advanced plasma sources. We present a combined experimental and theoretical study of unintended discharges in the narrow gaps of plasma processing chambers and report significant drop of the gas breakdown voltage in the presence of a background plasma facing the gap. Experimentally measured breakdown voltages decrease in subsequent breakdown events due to wall erosion caused by the discharge. Therefore, preventing and mitigating the first discharge is of paramount importance. An analysis of kinetic simulation results indicates that the charged particle influx from the background plasma in the processing chamber into the gap is responsible for the onset of early breakdown: higher charged particle density within the gap modifies the electric field profile, allowing unintended breakdowns to occur at a significantly reduced threshold voltage.