Evanescent electromagnetic field structures in inductively coupled plasma

Summary form only given. Inductively coupled plasma (ICP) has been recognized as a high-density plasma source in the radio frequency (RF) range for plasma application fields. Although the characterization and optimum plasma production have been actively tried, the role of the electron thermal motion especially in the low pressure regime has not been elucidated yet. In our previous studies (Shinohara et al., 1996, Takechi et al., 1997) this motion was investigated by measuring the skin depth of the evanescent wave and antenna-plasma resistance in a wide range of collision frequencies: For the ICP production, the dominant role of the collisionless (collisional) heating mechanism in the low (high) collisionality was demonstrated. Here, we present the effect of the electron thermal motion based on the non-local, collisionless model on the evanescent electromagnetic field structures in the ICP with a large diameter of 45 cm produced by a planar, spiral antenna. The axial profiles of the amplitude and phase of the evanescent electromagnetic fields by the magnetic probes and also the antenna-plasma loading resistance were measured, and they were compared with the theoretical models.