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P: Plasmaphysik

P 7: Poster: Niedertemperaturplasmen / Plasmatechnologie 3, Diagnostik 3

P 7.4: Poster

Freitag, 4. März 2005, 16:30–18:30, Poster HU

On The Application of the Quantum Cascade Laser-Absorption Spectroscopy for Plasma Process Monitoring — •Frank Hempel, Sven Glitsch, Jürgen Röpcke, and Stephan Saß — INP-Greifswald, Friedrich-Ludwig-Jahn-Str. 19, 17489 Greifswald, Germany

Plasmas containing molecular precursors are used in a variety of plasma enhanced chemical vapour deposition and etching systems to deposit or remove thin films. The key to an improved understanding and control of chemical active discharges is the analysis of the fragmentation of the precursor and the monitoring of transient or stable plasma reaction products, in particular the measurement of their ground state concentrations. This can be done by specific diagnostic methods using absorption spectroscopy (AS) in the mid infrared spectral region. Information on absolute concentrations of plasma species can be used e.g. for improvements of process effectiveness, reliability and reproducibility. This method also allows time resolved measurements. Mid infrared quantum cascade lasers (QCL) have become available recently. QCLs operate at room temperature and can have similar spectroscopic properties as e.g. lead salt diode lasers. Therefore QCLs are well suited for industrial applications, in particular for in-situ process control. Recently a QCL based absorption spectroscopic system, the No-dqQ-MACSNo-dq, has been developed and used to study dissociation processes of several precursor gases, as e.g. hydrocarbons or boron containing species, in industrial reactors. The applicability of Q-MACS and of QCLAS for on-line process monitoring has been proofed. Recent results of measurements and features of the Q-MACS are presented.