Electron Counting Detector Circuit with Analog Pipeline Buffering

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Solution Overview

Problem

Existing charged particle detection systems face challenges with signal-to-noise ratio (SNR) and throughput, particularly at low beam currents, due to the stochastic nature of electron arrival events, leading to high miscounting rates and poor energy discrimination accuracy.

Innovation Solution

A charged particle beam system with a detector circuit that includes a storage cell, multiplexer, threshold detector, and converter, configured to temporarily store and process signals representing electron arrival events, allowing for accurate counting and energy discrimination, and featuring an analog pipeline to reduce miscounts and ensure higher processing rates than average sensing element signal generation rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If basic circuitry is used to implement electron counting, then the system can detect charged particles, but high miscounting rates occur due to the stochastic nature of electron arrival events

Engineering Contradiction:

Improveelectron counting accuracyVSAvoidmiscounting rate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The detector is divided into multiple independent sensing elements, each with its own dedicated circuitry including storage cells, multiplexers, and converters. This segmentation allows parallel processing of electron arrival events, reducing the impact of stochastic variations in any single element and improving overall counting reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Storage cells are used to temporarily hold signals from sensing elements before processing. This preliminary action allows the system to buffer electron arrival events, ensuring that no events are lost due to timing variations and enabling accurate counting even when electron arrivals are stochastic.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If lower beam currents are used to enhance SNR in electron counting, then detection accuracy improves, but system throughput decreases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidsystem throughput

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

Multiple sensing elements operate simultaneously and continuously, with their signals processed through dedicated circuitry. This continuous parallel operation maintains high throughput even when individual elements operate at low beam currents to achieve high SNR, as the aggregate signal from multiple elements preserves detection accuracy while increasing overall system productivity.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system changes the parameter of beam current distribution by using multiple sensing elements at lower individual currents rather than a single element at high current. This parameter change allows the system to maintain high SNR through collective signal accumulation while achieving high throughput through parallel processing of multiple elements.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If faster processing is implemented to increase throughput, then system productivity improves, but miscounting rates increase due to insufficient processing time

Engineering Contradiction:

Improveprocessing rateVSAvoidcounting accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

Each sensing element has dedicated storage cells and processing circuitry, allowing parallel processing of multiple electron arrival events simultaneously. This segmentation enables the system to process signals faster without compromising accuracy, as each element's signal is independently captured and processed without interference from other elements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Storage cells act as intermediaries between sensing elements and the processing circuitry. These intermediaries temporarily hold signals, allowing the processing circuitry to operate at optimal speeds without losing signal integrity. The storage cells buffer the stochastic electron arrival events, enabling faster processing while maintaining counting accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution enhances the accuracy of electron counting and energy discrimination, reducing miscounting rates and improving SNR, enabling efficient detection even at low beam currents, thereby improving the overall throughput and image quality in charged particle beam systems.

Implementation Method 1

a sensing element configured to generate a signal in response to a charged particle arrival event

Methodology Applied

Scientific EffectCharged particle detection:

Data Source

PatentUS20230335372A1Sensing element level circuitry design for electron counting detection device

Publication Date: 2023.10.19 ASML NETHERLANDS BV

AI summary

A charged particle beam detector may include a circuit with a storage cell configured to receive a signal representing an output of a sensing element; a storage cell multiplexer configured to selectively transmit the signal representing the output of the sensing element to the storage cell; a threshold detector configured to compare the signal representing the output of the sensing element to a threshold; and a converter configured to perform signal processing on a signal transmitted from the storage cell.