Improvements in or relating to plasma reactors

A plasma reactor has a chamber (50) for containing a plasma and a passageway (60) communicating with the chamber is enhanced with a first removable plasma confinement magnet module placed adjacent the passageway including a first module housing (20,10) and a first plasma confinement magnet (80) inside the housing. It may further include a second removable plasma confinement magnet module placed adjacent the passageway including a second module housing (20,20), and a second plasma confinement magnet (82). Preferably, the first and second modules are located on opposite sides of the passageway. Moreover, the first and second plasma confinement magnets have magnetic orientations which tend to oppose plasma transport or leakage through the passageway. Preferably, the module housing includes a relatively non-magnetic thermal conductor such as aluminum and is in thermal contact with said chamber body. Cooling apparatus can be thermally coupled to the chamber body, whereby to maintain the first plasma confinement magnet below its Curie temperature. If the reactor includes a pumping annulus adjacent to a periphery of the chamber, then the passageway can be one which communicates between the chamber and the pumping annulus. Also, the passageway can be a wafer slit valve or a gas feed inlet. Such a gas feed inlet can be a center gas feed through a ceiling of the chamber. The module housing (20,20) can rest upon the chamber side wall and the chamber ceiling (52) can rest upon the module housing.