Detector Array Pass-Through Channels for Multi-Beam SEM Crosstalk
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Solution Overview
Problem
Existing electron beam imaging systems face challenges in inspecting deep semiconductor features like memory holes due to the impracticality of using secondary electrons for high throughput imaging and signal crosstalk between densely spaced beamlets, which degrades image clarity and resolution.
Innovation Solution
An electron multi-beam imaging system with a detector array that includes pass-through channels for individual beamlets, allowing closer placement to the sample to reduce crosstalk, and a retractable detector configuration for alternating imaging modes using secondary detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher densities of beamlets are used for high throughput imaging, then productivity is improved, but signal crosstalk between neighboring beamlets increases degrading image quality
Solution Approach 1:
The detector is divided into multiple independently controllable detector elements, each associated with a specific beamlet. This segmentation allows individual control of signal collection for each beamlet, enabling high beamlet density without crosstalk because each detector element only collects electrons from its associated beamlet's measurement region.
Solution Approach 2:
The invention transitions from conventional point detectors to a two-dimensional detector array where detectors are arranged in a plane corresponding to the beamlet arrangement. This dimensional change enables simultaneous detection from multiple beamlets while maintaining spatial separation of signals through the array structure.
2Productivity
If beamlets are densely spaced to increase imaging throughput, then productivity is improved, but crosstalk between neighboring beamlets creates ghost features reducing measurement precision
Solution Approach 1:
The detector surface is segmented into multiple discrete detector elements arranged in an array, with each element corresponding to a specific beamlet. This segmentation prevents crosstalk by ensuring that electrons from one beamlet are detected only by its associated detector element, eliminating ghost features even at high beamlet densities.
Solution Approach 2:
The detector array acts as an intermediary between the beamlets and the imaging system, providing spatially-resolved electron detection. Each detector element serves as a localized mediator that collects electrons from its corresponding beamlet's measurement region without interference from neighboring beamlets.
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 system enables high-throughput imaging of billions of features with improved signal quality and reduced crosstalk, achieving clearer images and higher resolution by utilizing both backscattered and secondary electrons effectively.
Implementation Method 1
one or more electron beam sources configured to generate a plurality of beamlets containing primary electrons
Implementation Method 2
an electron beamlet containing primary electrons directed to a sample generates secondary electrons (SEs) and backscattered electrons (BSEs)
Implementation Method 3
an electron beamlet containing primary electrons directed to a sample generates secondary electrons (SEs) and backscattered electrons (BSEs)
Data Source
AI summary
A system and method of an electron multi-beam imaging system is disclosed. The system may include an imaging sub-system. The imaging sub-system may include one or more electron beam sources configured to generate a plurality of beamlets to simultaneously probe a plurality of measurement regions on a sample. The imaging sub-system may further include one or more electron optics configured to adjust the plurality of beamlets. The imaging sub-system may further include a detector array, where the detector array includes a plurality of detectors configured to detect electrons emanating from a measurement region of the sample. For the system and method, each detector may include a pass-through channel configured for receiving a beamlet of the plurality of beamlets.