Wafer Defect Classification via Multi-Channel Scattering Analysis
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Solution Overview
Problem
Current wafer inspection systems are limited in their ability to effectively classify and distinguish between different types of defects, particularly yield-killing defects, as they often rely on size differentiation alone, which is insufficient for separating all killer defect types and those related to various manufacturing processes.
Innovation Solution
A computer-implemented method that utilizes different combinations of illumination and collection channels in an inspection system to identify defect types on wafers, selecting specific combinations based on the type of defect and wafer type, allowing for the use of unique characteristics such as scattering angle and intensity to differentiate between defect types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If size differentiation alone is used to classify defects, then the inspection system is simple to operate, but the ability to distinguish between different types of defects is insufficient
Solution Approach 1:
The patent transitions from single-dimension size-based classification to multi-dimensional classification by incorporating scattering angle and intensity measurements. The system uses multiple detection channels (first and second detection channels with different scattering angle ranges) to capture defect characteristics across multiple dimensions, enabling accurate differentiation between defect types such as particles, scratches, and pattern defects while maintaining ease of operation through automated multi-parameter analysis.
2Measurement precision
If multiple illumination and collection channels are used to identify defect types, then defect classification accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the detection system into multiple specialized channels: a first detection channel for collecting light at first scattering angles and a second detection channel for collecting light at second scattering angles. Each channel is optimized for specific defect type detection, allowing the system to handle complex classification tasks through divided functional components rather than a single complex detector, thus managing device complexity while improving measurement precision.
Solution Approach 2:
The inspection system is designed with multi-functional capability to detect various defect types (particles, scratches, pattern defects) using the same fundamental apparatus with different channel configurations. The system can adaptively select which detection channels to use based on the specific defect type being investigated, providing universal defect detection capability across multiple defect categories without requiring entirely separate systems for each defect type.
3Adaptability or versatility
If different combinations of illumination and collection channels are selected based on defect type and wafer type, then adaptability to different defect types is improved, but the system requires more complex selection logic
Solution Approach 1:
The patent implements dynamic channel selection where the inspection system automatically adapts its detection configuration based on the identified defect type and wafer type. The system can dynamically switch between different combinations of illumination and collection channels to optimize detection for specific defect characteristics, such as using particular channel combinations for particle detection versus scratch detection, thereby achieving high adaptability through programmed responsiveness rather than manual reconfiguration.
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 enables accurate and efficient classification of various defect types, including yield-killing defects, by leveraging the unique scattering patterns produced by different defects under different illumination and collection channel configurations, improving defect detection and process monitoring in semiconductor manufacturing.
Implementation Method 1
The output is acquired by different combinations of illumination and collection channels of the inspection system... leveraging the unique scattering patterns produced by different defects under different illumination and collection channel configurations
Data Source
AI summary
Various methods and systems for identifying defect types on a wafer are provided. One computer-implemented method for identifying defect types on a wafer includes acquiring output of an inspection system for defects detected on a wafer. The output is acquired by different combinations of illumination and collection channels of the inspection system. The method also includes identifying defect types of the defects based on the output acquired by a set of the different combinations. The set of the different combinations is selected based on the defect types to be identified on the wafer and a wafer type of the wafer such that a different set of the different combinations of the illumination and collection channels is used for identifying different defect types on different wafer types.