Mechanism of unintended breakdowns in advanced plasma sources in the semiconductor Industry*

Inductively or capacitively plasma sources used for crucial material processing such as etching in the semiconductor industry suffer from undesired breakdown within existing cylindrical narrow gaps of the plasma chamber. Such breakdowns reduce the reactor lifespan and compromise the wafer processing quality. Building on a previous study [1], this work elucidates the detailed mechanism of such breakdowns. Specifically, it is found that electron-induced secondary electron emissions predominantly trigger and maintain the breakdown. Based on this new understanding, mitigation strategies are proposed.  The investigation is performed using the explicit and cylindrical version of EDIPIC-2D, an open source Particle-In-Code specialized in the modeling of low-temperature plasmas. 

[1] S.H. Son, G. Go, W. Villafana, I.D. Kaganovich, A. Khrabrov, H.-C. Lee, K.-J. Chung, G.-S. Chae, S. Shim, D. Na, and J.Y. Kim, “Unintended gas breakdowns in narrow gaps of advanced plasma sources for semiconductor fabrication industry,” Applied Physics Letters 123(23), 232108 (2023).