Schottky TFE Beam Brightness Evaluation for Multi-Beam Current
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Solution Overview
Problem
Schottky thermal field emission sources exhibit strong non-uniformity, making it challenging to support multi-beam applications like multi-beam lithography or inspection tools, as conventional beam-defining apertures are not applicable for high incident beam currents, and there is a need to determine the usable current and brightness for forming multi-beam flows.
Innovation Solution
A method involving high-resolution emission imaging and experimentally developed algorithms to compute usable beam current and brightness by normalizing and summing pixel data values, assigning pixel currents based on intensity, and selecting pixels according to temperature-dependent criteria, allowing for the determination of usable current and brightness in Schottky TFE sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a beam-defining aperture is used to filter emission non-uniformity, then emission uniformity is improved, but beam current is reduced
Solution Approach 1:
The patent replaces the mechanical beam-defining aperture with a computational approach. Emission images are captured and processed digitally to calculate usable current and brightness, eliminating the need for physical aperture filtering while preserving beam current for multi-beam applications
Solution Approach 2:
The patent changes the approach from spatial filtering (aperture) to parameter-based evaluation. By measuring emission images and calculating brightness and usable current parameters, the system determines operational characteristics without physically restricting the beam, enabling high current operation for multi-beam tools
2Manufacturing precision
If a small beam-defining aperture is used to achieve uniform emission, then emission quality is improved, but applicability to multi-beam tools is reduced
Solution Approach 1:
The patent creates a universal evaluation method that works for both single-beam and multi-beam applications. By calculating usable current and brightness parameters from emission images, the system provides information applicable to various tool types without requiring physical modification or aperture selection
Solution Approach 2:
The computational evaluation system replaces the mechanical aperture selection process, providing a universal method to assess Schottky TFE performance for any application type, whether single-beam or multi-beam, without physical constraints
3Quantity of substance
If high beam current is required for multi-beam formation, then multi-beam capability is enabled, but emission non-uniformity becomes more significant
Solution Approach 1:
The patent uses emission image feedback to calculate usable current and brightness. By continuously measuring the actual emission distribution and computing parameters based on these measurements, the system characterizes the non-uniform emission and determines the usable portion for multi-beam formation
Solution Approach 2:
The patent transforms the emission non-uniformity problem into a parameter evaluation opportunity. By measuring and calculating brightness and usable current parameters from the non-uniform emission images, the system quantifies the usable beam current available for multi-beam applications despite the non-uniformity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate evaluation and optimization of Schottky TFE operation for multi-beam tools by identifying usable current and brightness, maximizing performance and image quality, and supporting high-resolution e-beam tools.
Implementation Method 1
A Schottky TFE source can be quite effective for implementing commercial e-beam tools such as a scanning electron microscope (SEM). Inherently, a Schottky TFE emission is strongly non-uniform
Data Source
AI summary
A system for determining Schottky thermal field emission (TFE) usable current and brightness of a Schottky TFE source is provided, the system including: one or more processors, configured to: acquire and store in a memory a Schottky TFE emission image in a digital format; and determine Schottky TFE usable beam current and brightness for the based on experimentally developed algorithms that utilize usable current criteria and usable emission current density, the usable current criteria being generated based on properties of a central beam component and an outer beam component of Schottky TFE beam current.