J. Phys. IV France 11 (2001) Pr3-1153-Pr3-1159
NIR diode laser based process control for industrial CVD reactorsV. Hopfe1, D.W. Sheel2, D. Raisbeck2, J. M. Rivero2, W. Graehlert1, O. Throl1, A.M.B. van Mol3 and C.I.M.A. Spee3
1 Fraunhofer Institute of Material and Beam Technology, Winterbergstrasse 28, 01277 Dresden, Germany
2 Pilkington Technology Management Ltd., Hall Lane, Lathom, Ormskirk, Lancashire L40 5UF, U.K.
3 TNO TPD, P.O. Box 595, 5600 Eindhoven, The Netherlands
The proposed new technical approach for CVD process control is characterised by a "chemistry based" feedback system with in-situ optical data as input information. The selected optical sensors continuously analyse the gas phase near the surface of the growing layer. The spectroscopic data has been correlated with process performance and layer properties, which in turn establish a data basis for process control. Diode laser spectroscopy in the near infra red (NIR-DLS) has been successfully applied for monitoring industrial CVD reactors. This technology has some notable potential advantages for production process applications. For example, the technology is robust and simple to operate, interference between species detection can be reduced, and simultaneous multi-point monitoring is readily achieved. The new process control approach is currently being verified on different industrialised CVD coaters. The paper will present some results of recent process monitoring studies on deposition of SnO2 layers on glass, based on the oxidation of (CH3)2SnCl2, which is used in high volume production for low-E glazings. Kinetic investigations support the empirically determined stiff correlation between gas phase composition and deposition rate.
© EDP Sciences 2001