Fluorescent Conversion for Multi-Beam Inspection Throughput
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional single electron beam inspection systems in the semiconductor industry face low throughput due to long scanning times and a limited signal-to-noise ratio, which restricts productivity and resolution, making them impractical for production-level inspections.
Innovation Solution
The method involves generating multiple primary beams focused onto a specimen surface, converting secondary charged particles into optical beams, and detecting these optical beams, allowing for closer beam arrangement and improved productivity by reducing interference and increasing data transport flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple primary beams are used in parallel to increase productivity, then inspection throughput is improved, but detector dimensions and electrical data transport become limiting factors
Solution Approach 1:
The patent replaces the direct electrical detection system with an optical conversion system. Secondary electron beams are converted into optical beams using fluorescent material, and optical detectors (photodetectors) are used instead of electronic detectors. This substitution eliminates the limitations of electrical data transport and detector dimensions, allowing for scalable multi-beam systems with improved productivity.
Solution Approach 2:
The patent introduces fluorescent material as an intermediary between the secondary electron beams and the detectors. This intermediary converts the secondary electron beams into optical beams, enabling the use of optical detectors and eliminating the direct electrical connection requirements that limit multi-beam system scalability.
2Productivity
If electron beam current is increased to improve scanning speed, then productivity is improved, but resolution deteriorates due to Coulomb interactions
Solution Approach 1:
The patent divides the single electron beam system into multiple parallel electron beams. Each beam operates at lower current, maintaining resolution, while the collective array of beams achieves high productivity. This segmentation allows independent optimization of each beam's parameters without the constraints of a single high-current beam.
Solution Approach 2:
The patent transitions from a single-beam temporal scanning approach to a multi-beam spatial parallel approach. Instead of increasing current in one beam to improve speed, multiple beams operate simultaneously in parallel, achieving high productivity through spatial distribution rather than temporal sequencing.
3Manufacturing precision
If a single electron beam is used to maintain resolution, then manufacturing precision is improved, but scanning time increases resulting in low productivity
Solution Approach 1:
The inspection task is segmented across multiple parallel electron beams, each maintaining low current for high resolution. The collective array of segmented beams covers the specimen surface simultaneously, achieving both high resolution and high productivity that cannot be achieved with a single beam.
Solution Approach 2:
The patent enables continuous inspection of multiple regions simultaneously using parallel beams, eliminating the sequential scanning limitation of single-beam systems. All beams operate continuously and simultaneously, maximizing productivity without compromising resolution.
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 approach enhances inspection productivity by enabling closer primary beam placement, reducing multiplicity limitations, and improving data transport efficiency, leading to faster and more accurate inspection processes.
Implementation Method 1
converting means for converting at least one of the collected secondary beams into an optical beam
Data Source
AI summary
The invention relates to a method of inspecting a specimen surface. The method comprises the steps of generating a plurality of primary beams directed towards the specimen surface, focussing the plurality of primary beams onto respective loci on the specimen surface, collecting a plurality of secondary beams of charged particles originating from the specimen surface upon incidence of the primary beams, converting at least one of the collected secondary beams into an optical beam, and detecting the optical beam.