Photoelectric e-Beam Inspection for Dynamic Defect Sensitivity
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Solution Overview
Problem
Current e-beam inspection techniques suffer from low sensitivity in detecting certain types of defects, such as plug leakage, short, or open defects, and are not sensitive to material composition, limiting sensitivity and throughput, and do not support dynamic inspection due to long stabilization times.
Innovation Solution
A charged particle beam system with a primary and secondary source is used to emit a beam and irradiate a sample, varying parameters of the secondary source to acquire multiple images, generating defect distributions at different parameter values, enhancing defect detection by capturing structural and compositional differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage contrast imaging with pre-charging is used to enhance defect detection sensitivity, then defect detection sensitivity is improved, but inspection time increases due to long stabilization times
Solution Approach 1:
The system performs pre-charging of the sample surface before the actual inspection to establish stable voltage contrast conditions. This preliminary action prepares the sample in advance, allowing faster subsequent inspection while maintaining high defect detection sensitivity through enhanced voltage contrast imaging.
Solution Approach 2:
The inspection process uses periodic pulsing of the charged particle beam, alternating between inspection pulses and recharging pulses. This periodic action maintains stable voltage contrast conditions throughout the inspection, eliminating the need for long stabilization times while preserving high defect detection sensitivity.
2Productivity
If a single parameter setting is used for inspection, then inspection speed is improved, but defect detection sensitivity decreases for certain defect types
Solution Approach 1:
The system dynamically adjusts inspection parameters during the inspection process based on the detected defect types and patterns. By making parameters adaptive rather than static, the system maintains high inspection speed while automatically optimizing sensitivity for different defect types encountered during the scan.
Solution Approach 2:
The system varies inspection parameters such as beam energy, pulse duration, and recharging frequency to optimize detection of different defect types. This parameter variation allows the system to maintain high speed inspection while achieving high sensitivity across multiple defect categories including plug leakage, short, and open defects.
3Device complexity
If standard e-beam inspection is used, then system complexity is kept low, but the ability to detect material composition differences is lost
Solution Approach 1:
The system introduces a secondary electron source as an intermediary to provide additional excitation of the sample. This secondary source complements the primary beam by providing different interaction mechanisms that reveal material composition differences, while the overall system architecture remains relatively simple and integrated.
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 method improves defect detection sensitivity and captures additional information about features, enabling the detection of defects that were previously undetectable, and provides dynamic e-beam inspection with high flexibility.
Implementation Method 1
a primary source configured to emit a charged particle beam along an optical axis onto a region of a sample
Implementation Method 2
In voltage contrast imaging, a charged particle beam system may scan a primary beam across a sample while secondary irradiation is applied to add a surface charge to the sample
Data Source
AI summary
A charged particle beam system may include a primary source, a secondary source, and a controller. The primary source may be configured to emit a charged particle beam along an optical axis onto a region of a sample. The secondary source may be configured to irradiate the region of the sample. The controller may be configured to control the charged particle beam system to change a parameter of an output of the secondary source. A method of imaging may include emitting a charged particle beam onto a region of a sample, irradiating the region of the sample with a secondary source, and changing a parameter of an output of the secondary source. A method of detecting defects may include inspecting a sample, generating a first defect distribution, and generating a second defect distribution.