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Home > Seminars and Workshops > Past seminars, PhD & HDR defense > 2009 > Séminaires 2009 > Jeudi 15 janvier 2009 à 11h

Jeudi 15 janvier 2009 à 11h

Jean-Paul Booth

Nouvelle sonde électrostatique pour le contrôle des réacteurs à gravure par plasma pour l’industrie

Jeudi 15 janvier 2008 à 11h


A key step in the fabrication of integrated circuits is the plasma etching of nanometer-scale features in thin layers of SiO2-based insulators. The trenches and via holes thus formed are then filled with metal to form the interconnection networks allowing the underlying transistors to be accesses. The etching, though a lithographic mask, is accomplished using radio-frequency excited plasmas in halogen-containing gases. The move to 300mm wafers and to smaller critical dimensions (currently 45nm in production), accompanied by increasing pressure on cost control has brought us to the point where open-loop control of the plasma conditions is no longer adequate. Therefore there is a need for advanced sensors which can directly monitor the plasma environment to which the processed wafer is exposed. Combined with Advanced Process Control (APC) methodologies these can improve the etch tool’s productivity in three key areas: improved product yield (chamber matching, fault detection and prediction, drift correction, chamber wall state characterization), throughput (reducing unnecessary process time and tool down-time) and lowering cost-of-ownership (minimizing unnecessary plasma exposure of consumable reactor parts).

During my two years at Lam research Corporation in California I implemented the deposition-tolerant ion flux probe described by Braithwaite et al. (1) as an in-situ process monitoring sensor on a commercial dielectric etch tool. The probe head is integrated into the upper (grounded) electrode and is made of the same material, and has been shown to have negligible process impact. With the use of an embedded digital signal processor to analyze the current-voltage characteristics in real-time, this sensor delivers high-precision time-resolved measurements (at 10 Hz) of the ion flux, electron temperature and probe floating potential. In addition, if there are thin films deposited on the probe, the film thickness and conductivity can be determined. This gives unprecedented insight into the power delivery, gas composition and surface state of the reactor during wafer processing. This talk will explore how this information can be used to improve the yield, throughput and cost-of-ownership of production etch tools.

1) N. St.J. Braithwaite, J.P. Booth, and G. Cunge, Plasma Sources, Science and Technol., 5, 677, (1996).

Tutelles : CNRS Ecole Polytechnique Sorbonne Université Université Paris Sud Observatoire de Paris Convention : CEA
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