Self-consistent modeling of plasma density control using self-excited electron resonance spectroscopy
- Siemens AG, Munich (Germany)
- Adolf-Slaby Inst., Berlin (Germany)
Plasma processing, such as the structuring of wafer surfaces or the deposition of thin films, plays a pivotal role in the manufacturing of VLSI microelectronics and other semiconductors. Increasing wafer diameters and decreasing device dimensions put an ever-growing demand on the stability of the process conditions. Closed loop feed-back control is thought to ensure this stability, even in the presence of run-to-run variations in the chamber state, or similar drifts in the external process parameters. Traditional plasma diagnostics either provides very indirect plasma information, or causes intolerable disturbances of the process itself. Recently, however, a novel method was proposed which allows to characterize an RF plasma in a strictly passive way. This method, termed Self-Excited Electron Resonance Spectroscopy or SEERS, is based on the excitation of global oscillations in the plasma body due to nonlinearities in the sheath. In this work, the authors study the behavior of an inductively coupled, high density plasma reactor (ICP/HDP) under the action of a SEERS-based closed loop control. The approach employs a period-averaged plasma simulator which allows to predict, for any input power P, the secular evolution of the charge distribution in the plasma bulk, and the spatially resolved capacitance of the boundary sheath. Note that the control scheme is realizable, in the sense that it makes use only of that plasma information which is physically available. The results show that already a simple--even only proportional--SEERS-based feedback control can considerably increase the long time stability of industrial plasma processes.
- OSTI ID:
- 346901
- Report Number(s):
- CONF-980601-; TRN: IM9920%%118
- Resource Relation:
- Conference: 25. international conference on plasma science, Raleigh, NC (United States), 1-4 Jun 1998; Other Information: PBD: 1998; Related Information: Is Part Of IEEE conference record -- Abstracts. 1998 IEEE international conference on plasma science; PB: 343 p.
- Country of Publication:
- United States
- Language:
- English
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