Environmental scanning electron microscope (ESEM/SEM) gas injection apparatus with anode integrated with gas concentrating structure
First Claim
1. An apparatus for providing a gas at a work piece surface in a vacuum chamber, comprising:
- a gas concentration structure for concentrating a gas at a shrouded region of the work piece, the gas concentration structure having an aperture for passing a beam to the work piece, the shrouded region being less than an entirety of the work piece, the aperture being sufficiently small to limit a conductance of the gas through the aperture;
a gas concentration structure support member for supporting the gas concentration structure, the gas concentration structure support member being moveable to position the gas concentration structure to concentrate the gas near a region of interest on the work piece; and
a gas conduit for providing the gas to a space within the gas concentration structure,wherein the gas concentration structure comprises an anode configured to;
cause an ionization of the concentrated gas;
drive positive ions generated by the ionization towards the work piece surface; and
detect a secondary electron signal amplified by the ionization.
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Accused Products
Abstract
A gas injection system provides a local region at the sample surface that has sufficient gas concentration to be ionized by secondary electrons to neutralize charged on the sample surface. In some embodiments, a gas concentration structure concentrates the gas near the surface. An optional hole in the gas concentration structure allows the charged particle beam to impact the interior of a shrouded region. In some embodiments, an anode near the surface increases the number of ions that return to the work piece surface for charge neutralization, the anode in some embodiments being a part of the gas injection system and in some embodiments being a separate structure.
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Citations
22 Claims
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1. An apparatus for providing a gas at a work piece surface in a vacuum chamber, comprising:
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a gas concentration structure for concentrating a gas at a shrouded region of the work piece, the gas concentration structure having an aperture for passing a beam to the work piece, the shrouded region being less than an entirety of the work piece, the aperture being sufficiently small to limit a conductance of the gas through the aperture; a gas concentration structure support member for supporting the gas concentration structure, the gas concentration structure support member being moveable to position the gas concentration structure to concentrate the gas near a region of interest on the work piece; and a gas conduit for providing the gas to a space within the gas concentration structure, wherein the gas concentration structure comprises an anode configured to; cause an ionization of the concentrated gas; drive positive ions generated by the ionization towards the work piece surface; and detect a secondary electron signal amplified by the ionization. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 20)
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11. A method of operating a charged particle beam system to process a work piece in a sample vacuum chamber, comprising:
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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. - View Dependent Claims (12, 13, 14, 15, 16, 21)
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17. An apparatus for providing a concentration of a gas at a work piece surface in a vacuum chamber, comprising:
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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. - View Dependent Claims (18, 19, 22)
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Specification