Sputtered contamination shielding for an ion source

Shielding associated with an ion source, such as an anode layer source, reduces the amount and/or concentration of sputtered contaminants impinging and remaining on the surface of a target substrate. While passing the ion beam through to the target substrate, shielding can reduce the total amount of sputtered contaminants impinging the substrate before, during, and/or after passage of the substrate through the envelope of the etching beam. Particularly, a shield configuration that blocks the contaminants from impinging the substrate after the substrate passes through the etching beam (i.e., outside of the envelope of the etching beam) yields a higher quality substrate with reduced substrate contamination.