Study On The Effect Of Magnetic Field On The Uniformity Of RF Inductive Coupled Plasma

Cryogenic plasma plays an increasingly important role in traditional and emerging industries,and RF plasma,as an important type of plasma which have been widely concerned and studied by people.Rf ion sources are playing an increasingly important role in material modification,etching and thin film deposition.Especially in the modern film preparation technology,ion beam sputtering has the advantages of less pollution,easy to accurately control the film forming conditions,accurate adjustment of ion beam energy and beam flow,and favorable to obtain high-quality films.In general plasma discharge,high density and uniformity of plasma is often restrict each other,although under certain conditions to improve discharge pressure,will be able to get a higher density of plasma,but with the increase of the discharge pressure,the inside of the plasma collision aggravate will become a hindrance in plasma diffusion which restricted its uniformity.Magnetic field has an important effect on plasma density,electron density and electron temperature of RF plasma.In this paper,the influence of magnetic field on electron density and uniformity of RF inductive coupled plasma is studied by means of simulation and experiment.Simulation results show that magnetic field has a positive effect on electron density and electron density distribution uniformity of plasma discharge.The influence on electron temperature and electron temperature uniformity is not obvious.The spectral measurement results show that the spectral intensity of each particle increases with the increase of magnetic field,especially the increase of excited oxygen atom.Under the discharge of Ar/O system,the spectral intensity of each particle increases with the increase of magnetic field.Under the same discharge condition,the higher proportion of argon can make the spectral intensity of excited argon atom and argon ion stronger,however,it is not certain that the higher proportion of oxygen can make the spectral intensity of excited oxygen atom and oxygen ion stronger.The result of probe diagnosis shows that the maximum span of electron density of plasma discharge increases from 4.03×1015(1/m3)to 1.16×1016(1/m3)with the introduction of external magnetic field,while the maximum span of electron density uniformity increases from 29.26%to 93.42%.However,the influence of magnetic field on the intensity and uniformity of electron temperature is not obvious.The span of electron temperature is only about 0.6eV,and the span of electron temperature uniformity is only about 6%.The experimental results of oxygenation characterization showed that the oxygenation uniformity of titanium sheet increased by 20 percent(from about 75%to about 95%)with the introduction of external magnetic field.It is proved that the improvement effect of magnetic field on RF inductive coupled plasma can be applied in practical engineering.Based on the results of simulation,spectral diagnosis,probe measurement and characterization experiments,it is proved that the introduction of external DC magnetic field in RF inductive coupled plasma discharge can improve the electron density and uniformity of plasma discharge in a certain range.