Abstract: A plasma reactor includes a series of parallel disposed electrodes carried in a vacuum vessel chamber. The series of electrodes is adapted to have alternate polarities. Supporting brackets are provided for positioning workpieces, such as multilayer printed circuit boards, parallel to and between electrodes of alternate polarities. The supporting brackets are electrically isolated from the electrodes. Furthermore, a uniform gas flow is directed across the surfaces of the workpieces upon their being subjected to a gas discharge plasma, by providing the plasma reactor with a parabolically-shaped door defining a parabolic surface within the vacuum vessel chamber, as well as vertically disposed baffle plates and at least three radial gas inlets located equidistantly about said chamber. The radial gas inlets have discharge ends directed at the parabolic surface of the door and are located between the baffle plates and the parabolic door surface.