Patent ID: 7695590

Claim:
A plasma reactor for processing a semiconductor workpiece, comprising: a reactor chamber; a set of plural parallel ion shower grids stacked together that divide said chamber into an upper ion generation region and a lower process region, said process region containing no grids, each of said ion shower grids having plural collinear cylindrical hole orifices from grid to grid, each orifice being oriented in a transverse direction relative to a surface plane of the respective ion shower grid; a workpiece support in said process region facing the lowermost one of said ion shower grids whereby said process region is bounded between the lowermost one of said ion shower grids and said workpiece support; a reactive species source for furnishing into said ion generation region a chemical vapor deposition precursor species; a vacuum pump coupled to said process region; a plasma source power applicator for generating a plasma in said ion generation region; a grid potential source of radio frequency (RF) power coupled to said set of ion shower grids, the orifices through at least some of said ion shower grids having: (a) an aspect ratio sufficient to limit ion trajectories in said process region to a narrow angular range about said non-parallel direction, (b) a resistance to gas flow sufficient to support a pressure drop between said ion generation and process regions of about at least a factor of 4.