“Alcatel" plasma etching reactor
This reactor is so called in relation to its plasma source. It is an inductively coupled source with a cylindrical geometry consisting of an alumina tube surrounded by a circular "half Nagoya III" antenna. This source is powered by a 13.56 MHz RF generator, with a maximum power of 1500 W. The substrate holder, located in the diffusion chamber beneath the plasma source, receives 4" diameter wafers and is equipped with a mechanical clamping ring. Its temperature is controlled by a thermostat (-40 / +60°C), He injection on the back side of the wafer ensures heat transfer. The substrate holder can be RF biased (13.56 MHz – 600 W max).
The vessel is equipped with several ports allowing plasma diagnosis by means of optical emission or absorption spectrometry (200 – 1000 nm), mass spectrometry (0.3 – 300 amu) and electrostatic probes. A multi-wavelength (412 – 730 nm) UV-visible ellipsometer allows real-time monitoring of the process; with direct access to etching kinetics in the case of transparent thin films (Figure 1). This reactor is coupled to a surface analysis chamber (SPECS) by a vacuum transfer system (Figure 2).
Equipped with ten gas lines, this reactor is dedicated to plasma etching processes operated in fluorinated (SF6, fluorocarbon) gases, alkane-hydrogen mixtures or liquid organic precursors in mixtures with O2, N2 and Ar.
Figure 1 : “Alcatel" plasma etching reactor : in front monochromator for optical spectroscopy (emission and absorption).
Figure 2 : Scheme of sample transfert under Ultra High Vacuum between Alcatel chamber and surface analysis chamber SPECS