Mirror Electron Projection Defect Inspection Precharge Optimization
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Solution Overview
Problem
Existing mirror electron projection and multi-beam scanning type electron beam inspection technologies lack adequate condition setup capabilities for optimizing precharge conditions, leading to suboptimal defect detection in semiconductor wafers.
Innovation Solution
A method and apparatus for condition setup in mirror electron projection or multi-beam scanning type scanning electron beam systems, which involves a charging step to form an electrical potential distribution, a detection step to capture secondary or reflected electrons, and a discharging step, while varying irradiation conditions to determine and optimize precharge conditions for defect inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mirror electron projection type or multi-beam scanning type electron beam apparatus is used to emit planar electron beam for throughput enhancement, then inspection speed and productivity are improved, but adequate condition setup capability for optimizing precharge conditions is lacking, leading to suboptimal defect detection
Solution Approach 1:
The patent implements a condition setup process that performs preliminary optimization of precharge conditions before actual defect inspection. The system automatically determines optimal precharge conditions by evaluating mirror image signals obtained under various charging conditions, storing the best conditions for subsequent use. This preliminary action resolves the contradiction by automating the condition setup that would otherwise be manual and time-consuming, enabling both high productivity and optimal detection conditions.
Solution Approach 2:
The system performs self-optimization by automatically evaluating its own operating conditions. The condition setup process uses the apparatus itself to generate mirror image signals under different precharge conditions, compares these signals, and determines the optimal conditions without requiring external intervention. This self-service capability allows the high-speed mirror electron projection system to automatically configure optimal detection parameters, resolving the ease of operation concern while maintaining high productivity.
2Ease of manufacture
If precharge conditions are not optimized, then inspection process is simpler, but defect detection accuracy is reduced
Solution Approach 1:
The patent implements a condition setup process that performs preliminary optimization of precharge conditions before actual defect inspection. The system automatically determines optimal precharge conditions by evaluating mirror image signals obtained under various charging conditions, storing the best conditions for subsequent use. This preliminary action resolves the contradiction by automating the condition setup that would otherwise be manual and time-consuming, enabling both high productivity and optimal detection conditions.
Solution Approach 2:
The system uses feedback from mirror image signal evaluation to automatically optimize precharge conditions. During the condition setup process, the apparatus generates mirror image signals under different charging conditions, compares these signals to determine which conditions produce the best defect detection contrast, and stores this feedback information as the optimal precharge conditions. This feedback mechanism ensures high defect detection accuracy while keeping the actual inspection process simple, as the optimization is already completed beforehand.
3Measurement precision
If multiple charging conditions are evaluated to determine optimal precharge conditions, then defect detection accuracy is improved, but inspection time increases
Solution Approach 1:
The patent implements a condition setup process that performs preliminary optimization of precharge conditions before actual defect inspection. The system automatically determines optimal precharge conditions by evaluating mirror image signals obtained under various charging conditions, storing the best conditions for subsequent use. This preliminary action resolves the contradiction by automating the condition setup that would otherwise be manual and time-consuming, enabling both high productivity and optimal detection conditions.
Solution Approach 2:
The system performs self-optimization by automatically evaluating its own operating conditions. The condition setup process uses the apparatus itself to generate mirror image signals under different precharge conditions, compares these signals, and determines the optimal conditions without requiring external intervention. This self-service capability allows the high-speed mirror electron projection system to automatically configure optimal detection parameters, resolving the ease of operation concern while maintaining high productivity.
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
Enables the setting of optimal precharge conditions for efficient defect detection in semiconductor wafers, improving the accuracy and speed of identifying pattern defects using mirror image signals.
Implementation Method 1
a charging step of using the mirror electron projection type or multi-beam scanning type defect inspection scanning electron beam apparatus to irradiate an inspection region on the defect inspection specimen with a charging electron beam under the precharge conditions determined in the condition setup process, charge the inspection region, and form an electrical potential distribution near the inspection region
Implementation Method 2
the detection step sheds a mirror electron projection or multiple electron beam onto the inspection region on which the electrical potential distribution is formed in the charging step to let a detector detect secondary electrons or reflected electrons generated from the surface and proximity of the specimen
Data Source
AI summary
The present invention provides a mirror electron projection (MPJ) type (SEPJ type included) scanning electron beam apparatus that is capable of performing condition setup, and a method and apparatus for inspecting pattern defects with the scanning electron beam apparatus. A mirror electron projection type defect inspection apparatus, which comprises a charging device for emitting a charging electron beam, electron beam irradiation means for shedding a mirror electron projection electron beam onto an inspection region near which an electrical potential distribution is formed, detection means for detecting secondary electrons or reflected electrons generated from a surface and proximity of the specimen, and defect detection means for detecting a defect by processing a mirror image signal that is detected by the detection means, includes irradiation condition optimization means for optimizing charging electron beam irradiation conditions.