Annular Backscatter Detector Layout for Deep Defect Inspection
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Solution Overview
Problem
Existing electron beam inspection systems for EUV lithography lack the capability to accurately detect and characterize defects with high resolution, particularly deep defects, which can impact the yield and performance of semiconductor devices.
Innovation Solution
The integration of an electron beam inspection system with programmable angle and energy detection, utilizing backscattering detectors with annular geometry and semiconductor devices like silicon-based photodiodes, avalanche photodiodes, and PIN diodes, to generate energy-angle mappings of backscattered electrons, providing detailed compositional and structural information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electron beam inspection systems are used, then basic defect detection is possible, but detection precision for deep defects is insufficient
Solution Approach 1:
The detection system is segmented into multiple detector elements arranged in specific geometric patterns (e.g., tetrahedral configurations). Each detector element captures backscattered electrons from specific angular perspectives, and the combined data from multiple segments enables precise three-dimensional defect characterization that overcomes the limitations of single-detector systems.
Solution Approach 2:
The patent transitions from two-dimensional detector arrangements to three-dimensional detector configurations, positioning detectors at multiple spatial coordinates around the sample. This dimensional expansion allows simultaneous measurement of backscattered electrons from multiple angles and depths, dramatically improving the detection precision for deep defects while maintaining manageable system complexity through systematic geometric arrangements.
2Loss of information
If simple detection methods are used, then system operation is easy, but information completeness about defects is insufficient
Solution Approach 1:
The multi-element detector system serves multiple functions simultaneously: it detects backscattered electrons from various angles, determines defect depth, characterizes defect geometry, and provides compositional information. This universal detection capability captures comprehensive defect information without requiring separate specialized systems, thereby reducing information loss while keeping operation relatively straightforward through integrated data acquisition.
Solution Approach 2:
The patent introduces computational algorithms and data processing intermediaries that automatically integrate signals from multiple detector elements. These intermediaries transform raw detector data into comprehensive defect characterizations, preserving complete information about defect properties while shielding operators from the complexity of multi-element data analysis, thus maintaining ease of operation.
3Measurement precision
If single-angle detection is used, then device complexity is low, but measurement precision for deep defects deteriorates
Solution Approach 1:
The detector system is divided into multiple segmented elements positioned at different angular locations around the sample. Each segment detects backscattered electrons from its specific viewing angle, and the combined information from all segments enables precise depth resolution and three-dimensional defect mapping, significantly improving deep defect detection precision while organizing complexity through systematic segmentation.
Solution Approach 2:
The patent employs composite detector configurations that integrate multiple detector types or elements with different detection characteristics into a unified system. This composite approach combines the advantages of various detector arrangements to achieve superior depth resolution and angular coverage for deep defect detection, managing complexity through harmonious integration of diverse detector components.
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
Enhances the detection of both shallow and deep defects by generating precise energy-angle mappings, improving the accuracy and reliability of defect identification in semiconductor manufacturing.
Implementation Method 1
utilizing backscattering detectors with annular geometry and semiconductor devices like silicon-based photodiodes, avalanche photodiodes, and PIN diodes, to generate energy-angle mappings of backscattered electrons
Data Source
AI summary
An electron detector includes a detector body having a detector surface with an annular geometry and a central aperture configured to allow a focused electron beam to pass through the detector body toward a sample. The detector surface is configured to face the sample, and a plurality of detector devices are located on the detector surface. Each of the plurality of detector devices is configured to generate an electrical signal in response to interaction with an electron backscattered from the sample. According to various embodiments, the plurality of detector devices includes at least a first two detector devices separated from one another along a radial direction along the detector surface and at least a second two detector devices separated from one another along an angular direction along the detector surface. The detector devices are configured to determine both a polar incidence angle and an azimuthal incidence angle of detected electrons.