Abstract: Processing tools, components of tools, and methods of making and using such devices for electrochemical processing of microelectronic workpieces. One aspect of the invention is directed toward reaction vessels for electrochemical processing of microelectronic workpieces, processing stations including such reaction vessels, and methods for using these devices. For example, one embodiment of a reaction vessel includes an outer container having an outer wall, a first outlet configured to introduce a primary fluid flow into the outer container, and at least one second outlet configured to introduce a secondary fluid flow into the outer container separate from the primary fluid flow. The reaction vessel can also include at least one electrode, and it can also have a field shaping unit.