Asymmetric Electrostatic Filter for Ion Beam Control

The patent applies asymmetry by configuring electrodes in an asymmetric arrangement rather than symmetric pairs. The electrostatic module includes a first electrode, second electrode, third electrode, and fourth electrode arranged asymmetrically to define a beam passage. This asymmetric configuration allows the ion beam to pass through while minimizing direct exposure of electrodes to sputtered material, thereby reducing contamination while maintaining beam control precision.

The patent introduces a spatial dimension solution by tilting the beam passage relative to the substrate surface. The beam passage is configured at an angle between 10 to 75 degrees relative to the substrate normal, creating a geometric relationship that prevents sputtered material from directly reaching the electrodes. This dimensional arrangement separates the electrode protection function from the beam control function, reducing contamination while preserving energy control capability.

The asymmetric electrode arrangement positions electrodes at different spatial locations and orientations relative to the beam passage. The first and second electrodes may be positioned on one side of the beam passage while third and fourth electrodes are positioned on another side, creating an asymmetric field configuration that achieves effective beam focusing while minimizing electrode exposure to harmful sputtered material, thereby improving both focusing capability and electrode durability.

The patent introduces the beam passage geometry and angular orientation as intermediary elements between the electrodes and the substrate. The tilted beam passage acts as a mediator that allows electrodes to maintain their focusing function while preventing direct line-of-sight exposure to sputtered material. This intermediary geometric configuration protects electrodes from erosion and flaking while preserving beam focusing precision.

The patent optimizes the beam bend angle parameter within a specific range (10 to 75 degrees relative to substrate normal) to achieve the optimal balance between neutral screening and energy stability. By configuring the beam passage at this optimized angular parameter, the system achieves effective screening of energetic neutrals while maintaining stable ion beam energy control, avoiding the deterioration that occurs with excessive bend angles.

The asymmetric configuration of the beam passage and electrodes creates an uneven geometric arrangement that provides effective neutral screening without requiring excessive beam bending. The asymmetric path allows ions to pass through while deflecting neutrals, achieving good screening effectiveness while maintaining beam energy stability through the optimized asymmetric geometry rather than symmetric large-angle bending.