Method and apparatus for usable beam current and brightness in Schottky thermal field emission (TFE)
AssigneesNuFlare Technology, Inc., NuFlare Technology America, Inc.
InventorsVictor Katsap, Chising Lai
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Abstract
The present disclosure is related to a Schottky thermal field emission (TFE) source for emitting an electron beam. Exemplary embodiments can provide the acquisition of high-resolution emission images of Schottky TFE source and compute usable beam current and brightness based on experimentally developed usable current criteria. Advantages of these exemplary embodiments include: (1) obtaining usable beam current and brightness of a Schottky TFE source can be important with reference to Schottky TFE development and quality inspection, and (2) optimizing Schottky TFE operation modes so as to maximize Schottky TFE usable beam current and brightness can enable operation of multi-beam electron optical tools.
Claims15
A method of determining a Schottky thermal field emission (TFE) usable current and brightness, the method comprising:
- configuring one or more processors for:
- acquiring and storing in a memory a Schottky TFE emission image of a Schottky TFE source in a digital format;
- normalizing and summing pixel data values of the acquired and stored Schottky TFE emission image;
- assigning a pixel current based on the normalized and summed pixel data values and a beam current, wherein the beam current comprises a central beam component and an outer beam component;
- and
- determining a Schottky TFE usable current and brightness based on the assigned pixel current and usable current criteria,
- wherein the assigning of the pixel current based on the normalized and summed pixel values and the beam current further comprises assigning each pixel a value proportional to each pixel's intensity, dividing the beam current by the sum of normalized pixel values, and assigning resulting division output, and
- wherein the assigned pixel current is introduced to each pixel based on a fraction of the beam current.
A non-transitory computer readable medium having instructions stored therein that, when executed by one or more processors, cause the one or more processors to perform a method to determine Schottky thermal field emission (TFE) usable current and brightness of a Schottky TFE source, the method comprising:
- acquiring and storing to a memory a Schottky TFE emission image in a digital format;
- normalizing and summing pixel data values of the acquired and stored Schottky TFE emission image;
- assigning a pixel current based on the normalized and summed pixel data values and a beam current, wherein the beam current comprises a central beam component and an outer beam component;
- and
- determining Schottky TFE usable current and brightness based on the assigned pixel current and usable current criteria,
- wherein the assigning of the pixel current based on the normalized and summed pixel values and the beam current further comprises assigning each pixel a value proportional to each pixel's intensity, dividing beam current by the sum of normalized pixel values, and assigning resulting fraction of the beam current to each pixel.
Dependencies are inferred from the claim text.