Recent results of multi-cathode electron beam plasma source

Abstract

The basic experiments of the multi-cathode electron beam plasma source (MCEBPS) were carried out recently, The MCEBPS has characteristics of uniform plasma in large area. It can be extended to produce uniform plasmas in a very large diameter of several meter with addition of the other cathodes. The plasmas an made through direct interaction of electrons and neutral gases in the wide area with a diameter of 300 mm or above. The non-uniformity of the radial plasma density must be small to be suitable for the process of next generation semiconductor devices. The MCEBPS now has seven cathodes (multi-cathode) whose array is concentric to produce uniform plasmas in a large area at the target position. The energy of extracted electron beam from cathodes is about 50 eV. This can be controlled by changing the voltages of extraction electrodes, The electron beam current can be also controlled to the desired value by adjusting the cathode temperatures. The energy and the current of the electron beam can be controlled independently. In the working chamber, plasmas for the process of target material are produced through the direct interaction of the extracted electron beam and the neutral gases which are fed from outside. The plasma density above 1 x 10(10) cm(-3) and uniformity below +/- 3.0% in diameter of 320 mm were achieved recently. The adoption of multipole or additional permanent magnets is under consideration to enhance the plasma confinement and uniformity. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.