Semiconductor Defect Detection via Fluorescent Contrast
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Solution Overview
Problem
Current inspection techniques for electronic devices, such as wafers and circuit boards, face challenges in detecting anomalies or candidate defects, particularly on metallic layers, due to limited contrast in intensity between the metallic layers and defects, which can lead to difficulties in identifying potential electrical failures.
Innovation Solution
An optical system that uses a combination of ultraviolet excitation light and a dichroic beam splitter to separate excitation light from fluorescent light emitted by non-metallic layers, allowing for enhanced contrast and detection of candidate defects through image analysis, utilizing sensors and controllers for automated processing and decision-making.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection techniques are used to examine metallic layers, then the inspection process is simple and fast, but the contrast between metallic layers and defects is insufficient leading to poor detection accuracy
Solution Approach 1:
The inspection process is segmented into multiple sequential stages: initial brightfield inspection for rapid overview, followed by fluorescent inspection for enhanced contrast detection. This segmentation allows the system to leverage the speed of simple inspection while achieving the precision of complex multi-modal inspection through systematic division of detection tasks.
Solution Approach 2:
A dichroic beam splitter is introduced as an intermediary optical component that selectively transmits fluorescent wavelengths while reflecting excitation light. This intermediary enables the separation and independent optimization of excitation and detection pathways, allowing the system to achieve high contrast defect detection without requiring complete system redesign.
2Measurement precision
If multiple inspection techniques are combined to improve defect detection, then detection accuracy improves, but inspection time and processing complexity increase
Solution Approach 1:
The brightfield and fluorescent inspection modalities are merged into a single integrated optical path using beam splitters and dichroic mirrors. This merging allows both inspection techniques to operate simultaneously on the same substrate without requiring separate inspection cycles, thereby maintaining high detection accuracy while minimizing inspection time through parallel operation.
Solution Approach 2:
The inspection system maintains continuous operation by eliminating idle transitions between inspection modes. The optical design enables seamless switching between brightfield and fluorescent detection without requiring substrate repositioning or system reconfiguration, ensuring that the useful inspection action continues uninterrupted throughout the process.
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 effectively identifies candidate defects with improved contrast, enabling reliable detection and assessment of potential electrical failures, allowing for appropriate further processing or rejection of substrates, thereby enhancing manufacturing yield and quality control.
Implementation Method 1
a light source (102) provided to illuminate a substrate (110)
Implementation Method 2
Some of the excitation light from source 102 is incident on materials, e.g. organic materials, which fluoresce upon absorbing light at an excitation wavelength
Implementation Method 3
An excitation light (e.g., ultraviolet) from the light source 102 is transmitted to a filter and beam splitter 120 which passes and reflects different wavelengths of light
Data Source
AI summary
Concepts presented herein relate to approaches for performing substrate inspection. In one aspect, the concepts relate to detecting anomalies or candidate defects on the substrate based on contrast in images obtained of the substrate.