Optimisation and characterisation of a TCP type RF broad beam ion source

A very compact type of broad beam ion source based on transformer coupled p lasma excitation (TCP) is described. Our ion source consists of a cylindric al RF coil surrounding the discharge vessel and a very compact, patented ma tching unit from special ceramics capacitors attached directly to the disch arge arrangement. However, the TCP excitation as well as the sophisticated layout of the matching unit require an optimum source arrangement due to th e beam parameters, the source lifetime and the performance of the RF elemen ts. For that reason, a global discharge model was applied together with an RF replacement circuit diagram to calculate for the optimum source layout. An advanced plasma and beam diagnostics is used for controlling the source performance due to beam composition, beam profile and ion energy distributi on. In this way, our RF source is adapted to different beam requirements in inert and reactive beam processes for etching, modification and sputter de position. (C) 2001 Elsevier Science B.V. All rights reserved.