Non-planar Extractor with Built-in Aperture for Electron Beam

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Solution Overview

Problem

Conventional electron sources suffer from poor vacuum conditions near the emitter due to a large trapped volume and require separate angular beam filtering, which complicates the electron beam generation process.

Innovation Solution

The use of a non-planar extractor with a built-in beam-limiting aperture, which allows for differential pumping and modular construction, effectively filters electron trajectories and maintains a high vacuum near the emitter, enhancing beam focus and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional planar extractor is used, then the structure is simple, but the vacuum conditions near the emitter are poor due to large trapped volume

Engineering Contradiction:
Improvestructural simplicityVSAvoidvacuum conditions
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The extractor is divided into multiple sections: an extractor opening through which electrons pass, and a beam-limiting aperture with a smaller opening. This segmentation creates distinct functional zones that reduce the trapped volume near the emitter while maintaining structural feasibility

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The beam-limiting aperture is nested within the extractor structure, with its opening positioned within the extractor opening. This nested configuration allows the beam-limiting function to be integrated into the extractor without significantly increasing overall structural complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If a conventional planar extractor is used, then the structure is simple, but separate angular beam filtering is required which complicates the system

Engineering Contradiction:
Improvestructural simplicityVSAvoidsystem complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The beam-limiting aperture is merged with the extractor structure, combining the extraction function and the angular beam filtering function into a single integrated component. This eliminates the need for separate beam filtering modules downstream

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The extractor structure serves multiple functions: it extracts electrons from the emitter and simultaneously acts as a beam-limiting aperture for angular filtering. This multi-functionality reduces the total number of components required in the electron source system

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If a non-planar extractor with built-in beam-limiting aperture is used, then vacuum conditions improve and beam focus stability improves, but the structure becomes more complex

Engineering Contradiction:
Improvebeam focus stabilityVSAvoidextractor structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The extractor structure has different properties in different regions: the extractor opening provides a larger passage for electron extraction, while the nested beam-limiting aperture provides a smaller opening for angular filtering. This local differentiation optimizes performance in each region without requiring complete structural redesign

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The beam-limiting aperture is positioned at a different spatial location within the extractor structure, creating a multi-level configuration. This dimensional arrangement allows both extraction and filtering functions to coexist without interfering with each other

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This configuration improves vacuum conditions, enables effective angular filtering close to the emitter, and facilitates easier component replacement, leading to improved electron beam generation and focus stability.

Implementation Method 1

An extraction electrode is provided for extracting the electron from the suppresser electrode so as to form the electron beam

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

an accelerating electrode is provided for accelerating the electron beam

Methodology Applied
Scientific EffectElectric field acceleration: Electric Field

Implementation Method 3

A capacitor electrode is provided for converging the electron beam

Methodology Applied
Scientific EffectElectrostatic lens: Electrostatic Lens

Data Source

PatentEP2847781B1Non-planar extractor structure for electron source
Publication Date: 2017.12.20 KLA CORP
  • EP2847781B1 patent drawingFigure 1
  • EP2847781B1 patent drawingFigure 2
  • EP2847781B1 patent drawingFigure 3

AI summary

One embodiment disclosed relates to an electron source for generating an electron beam. The electron source includes an electron emitter having a tip from which an electron beam is extracted. The electron further includes a non-planar extractor with an extractor opening and a built-in beam-limiting aperture. The extractor opening is larger than the beam-limiting aperture, and central axes of both the extractor opening and the beam-limiting aperture are aligned with the tip along a beam axis. Another embodiment relates to a method of generating an electron beam using an electron source having a non-planar extractor. Another embodiment relates to an array of electron sources for generating an array of electron beams. The array of electron sources includes an array of electron emitters and an array of non-planar extractor structures. Other embodiments, aspects and features are also disclosed.