Large area high density plasma source by helical resonator arrays

An array of smaller unit plasma sources has been used for generating a larg er area plasma to process large substrates such as flat panel displays. In this work, four helical resonators are distributed in a 2 x 2 array by modi fying the upper part of the conventional reactive ion etching type LCD etch er. Since the resonance condition of the individual unit can be easily foun d by adjusting the tapping position of RF signal to the helical antenna, on e RF power supply can be used for delivering the power efficiently to all f our helical resonators without an impedance matching network. Previous work using a 2 x 2 array inductively coupled plasma (ICP) requires one matching network and a variable capacitor to each ICP antenna for balancing the pow er delivery. Ion density and electron temperature are measured in terms of chamber pressure, gas flow rate and RF power for both oxygen and argon plas ma. By finding resonance conditions of four helical resonator units, oxygen plasma density of higher than 5 x 10(16)/m(3) with a uniformity of better than 10% can be obtained over the 40 x 40 cm(2) area. (C) 2000 Elsevier Sci ence B.V. All rights reserved.