Patent ID: 8187414

Claim:
A silicon-based showerhead electrode comprising a backside, a frontside, a plurality of showerhead passages, a plurality of backside recesses, and a plurality of backside inserts, wherein: the plurality of showerhead passages extend from the backside of the silicon-based showerhead electrode to the frontside of the silicon-based showerhead electrode; the plurality of backside recesses are formed in the backside of the silicon-based showerhead electrode, the backside recesses leaving a thickness of silicon-based electrode material between the recess and the frontside of the silicon-based showerhead electrode; the backside inserts are positioned in the backside recesses along the backside of the silicon-based showerhead electrode; the backside inserts comprise a threaded outside diameter, a threaded inside diameter, and a tool engaging portion formed in the threaded inside diameter; the tool engaging portion is formed such that the backside insert further comprises one or more lateral shielding portions between the tool engaging portion and the threaded outside diameter to prevent a tool engaged with the tool engaging portion of the backside insert from extending beyond the threaded outside diameter of the insert wherein the silicon-based electrode material comprises single crystal silicon.