Environmental scanning electron microscope (ESEM/SEM) gas injection apparatus with anode integrated with gas concentrating structure

A method of operating a charged particle beam system to process a work piece in a sample vacuum chamber, comprising:

• creating a region inside the vacuum chamber between a portion of a work piece surface and a as concentration structure having a first gas concentration higher than a second gas concentration elsewhere in a sample vacuum chamber, the portion of the work piece being smaller than an entire surface of the work piece and the gas concentration structure comprising an anode;
• directing a charged particle beam toward the work piece, the charged particle beam passing through the first gas concentration;
• applying a voltage to the anode such that the anode attracts secondary electrons generated from an impact of the charged particle beam, the secondary electrons causing an ionization cascade in the first gas concentration;
• neutralizing an electrical charge on a portion of the workpiece with positive ions from the ionization cascade;
• and
• detecting an electron current amplified by the ionization cascade using the anode to form an image.

An apparatus for providing a concentration of a gas at a work piece surface in a vacuum chamber, comprising:

• a gas concentrator comprising an anode and configured to provide a concentration of a gas at a portion of a work piece surface, the portion less than the entire work piece surface, in a vacuum chamber;
• and
• a gas conduit for providing the gas to the gas concentrator,
• wherein the anode is configured to:
• cause an ionization of the concentration of the gas;
• drive positive ions generated by the ionization towards the work piece surface;
• and
• detect a secondary electron signal amplified by the ionization.