Patent ID: 8349125

Claim:
A plasma cleaning apparatus for use with a charged-particle-beam instrument of the type having a vacuum chamber containing a specimen imaging area and a stage support rod for insertion and manipulation of specimens in the specimen imaging area with an exchange chamber in fluid communication between the vacuum chamber and an exterior of the instrument and through which the stage support rod passes into the vacuum chamber, the stage support rod including at least one sealing member to maintain vacuum in the chamber and at least one indexing member to assist in radially and axially positioning the stage support rod in the vacuum chamber, the apparatus comprising: a hollow rod dimensioned to replace the stage support rod, the hollow rod having a distal end and a sealing member and an indexing member substantially identical to those on the stage support rod to pass through said exchange chamber in place of the stage support rod while maintaining vacuum within the evacuated vacuum chamber; an electrode disposed at the distal end of the hollow rod, the electrode being an electrically conductive hollow cylinder, and having a diameter equal to or less than that of the hollow rod; a source of cleaning gas in selective fluid communication with the hollow rod; a sensor coupled to the hollow rod to measure pressure inside the rod; a control valve coupled to the hollow rod exterior of the vacuum chamber to control flow of cleaning gas into the hollow rod; and an electrical power source in electrical communication with the electrode, wherein the hollow rod and electrode are selectively positioned in the specimen imaging area within the cleaning gas delivered through the rod and to the electrode to generate a plasma that emits an excited gas proximal the specimen imaging area for oxidative cleaning the specimen imaging area.