CHARACTERIZATION OF AN AZIMUTHALLY SYMMETRICAL HELICON WAVE HIGH-DENSITY PLASMA SOURCE

A cylindrically symmetric (azimuthal mode number m=0) resonant inducti ve (MORI(TM)) radio frequency (rf) helicon wave high density plasma so urce is described. The source consists of an antenna and bell jar gene rator immersed in a diverging magnetic held. Plasma is generated in th is upstream region and then is transported along the field lines into the low-field downstream processing chamber. A propagating wave is obs erved in the plasma with rf spatial distribution and propagation chara cteristics that obey the theoretical m=0 helicon wave dispersion relat ion. By varying the divergence of the source magnetic field, the wafer etch rate and etch uniformity can be controlled. Spatially resolved o ptical emission spectroscopy shows that molecular gases are almost com pletely dissociated near the plasma center and have a uniform radial d istribution. Highly uniform plasma and neutral distributions are then produced at the wafer location, and have been used in a variety of etc h applications. (C) 1997 American Vacuum Society. [S073-2101(97)04206- 1].