Apparatus and method for secondary electron emission microscope
AssigneeKLA-Tencor Corporation
InventorsDavid L. Adler, David J. Walker, Fred Babian, Travis Wolfe
Life of this patent
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Abstract
An apparatus and method for inspecting a surface of a sample, particularly but not limited to a semiconductor device, using an electron beam is presented. The technique is called Secondary Electron Emission Microscopy (SEEM), and has significant advantages over both Scanning Electron Microscopy (SEM) and Low Energy Electron Microscopy (LEEM) techniques. In particular, the SEEM technique utilizes a beam of relatively high-energy primary electrons having a beam width appropriate for parallel, multi-pixel imaging. The electron energy is near a charge-stable condition to achieve faster imaging than was previously attainable with SEM, and charge neutrality unattainable with LEEM.
Claims45
A method of inspecting objects, comprising:
- providing a sample;
- directing an electron beam to be incident on a multi-pixel imaging region of said sample;
- simultaneously detecting electrons emitted from a plurality of pixels within the multi-pixel imaging region;
- and
- maintaining a stable electrostatic charge balance of said sample.
An apparatus for using electron beams to inspect objects, comprising:
- an electron beam source for directing an electron beam to be incident on a sample at a multi-pixel imaging region;
- and
- an electron detector coupled to the electron beam source to detect electrons emitted from the sample, where in the electron detector is configured to simultaneously image a plurality of pixels within the multi-pixel imaging region;
- and a means to maintain a stable electrostatic charge balance of said sample.
An apparatus for using electron beams to inspect objects, comprising:
- a primary electron beam generator for generating a primary electron beam having a width greater than about 0.1 millimeters for parallel multi-pixel imaging incident on a sample along a primary electron beam path;
- an electron collimating lens positioned along the primary electron beam path for collimating said primary electron beam;
- an electron objective lens positioned along the primary electron beam path for focusing said collimated beam at said sample and for collimating secondary electrons produced by said sample into a secondary electron beam along a secondary electron beam path;
- an electron focusing lens positioned along the secondary electron beam path for focusing said secondary electron beam at an image plane, the image plane being positioned along the secondary electron beam path adjacent the electron focusing lens;
- an electron detector for detecting an image pattern of said secondary electron beam at said image plane;
- and
- an electron beam separator for redirecting said primary electron beam towards said electron objective lens and said secondary electron beam towards said electron focusing lens, the electron beam separator being positioned along the primary electron beam path and the secondary electron beam path;
- and a means to maintain a stable electrostatic charge balance at said sample.
An apparatus for inspecting objects with electron beams, comprising:
- electron beam source means in communication with a sample for producing a primary electron beam having a width greater than about 0.1 millimeters along a primary electron beam path incident on said sample for parallel multi-pixel imaging;
- electron collimating lens means positioned along the primary electron beam path for collimating said primary electron beam;
- electron objective lens means for focusing said primary electron beam at said sample and for collimating secondary electrons produced by said sample into a secondary electron beam along a secondary electron beam path;
- electron detector means positioned along the secondary electron beam path for detecting an image pattern of said secondary electron beam at an image plane;
- electron projection lens means positioned alone the secondary electron beam path for focusing said secondary electron beam on said electron detector means at said image plane;
- and
- electron beam separator means positioned along the primary electron beam path and along the secondary electron beam path for redirecting said primary electron beam towards said electron objective lens and redirecting said secondary electron beam towards said electron projection lens means;
- and a means to maintain a stable electrostatic change balance of said sample.
A method of inspecting a structure, comprising:
- providing a sample;
- directing a primary electron beam to be incident an area of the sample comprising a plurality of pixels such that electrons are simultaneously emitted from each of the plurality of pixels;
- and
- detecting the emitted electrons by simultaneously imaging the electrons emitted from the area.
Dependencies are inferred from the claim text.