Multi-Wavelength Defect Inspection for Layer-Specific Detection
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Solution Overview
Problem
Existing defect inspection systems for semiconductor manufacturing lack consistency in detecting defects across multiple layers, particularly in distinguishing between surface and buried defects.
Innovation Solution
A defect inspection system utilizing a stage and a defect inspection apparatus with a light source unit emitting visible and infrared light, a beam splitter, an objective lens, and a detector to generate images of both surface and underlying layers, allowing for precise defect identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light source is used for defect inspection, then the inspection process is simple, but the consistency in detecting defects across multiple layers is poor
Solution Approach 1:
The inspection system is segmented into multiple independent light source units, each dedicated to inspecting specific layers. The first light source unit inspects the first layer while the second light source unit inspects the second layer, allowing each unit to be optimized for its specific layer's characteristics and achieving consistent defect detection across multiple layers
Solution Approach 2:
Each light source unit is designed with multi-functionality to perform multiple operations. The first light source unit can both irradiate the first layer for inspection and provide lighting for the second layer inspection, while the second light source unit similarly serves dual purposes, reducing overall system complexity while maintaining inspection consistency
2Measurement precision
If multiple light sources are used to inspect different layers, then defect detection consistency is improved, but the device complexity increases
Solution Approach 1:
The first light source unit merges multiple functions by simultaneously serving as the inspection light source for the first layer and as the illumination source for the second layer. This consolidation reduces the total number of light source units needed, improving defect detection consistency while limiting the increase in device complexity
3Measurement precision
If visible light is used for inspection, then the inspection process is simple, but the ability to distinguish surface and buried defects is limited
Solution Approach 1:
Different light sources with specific local qualities are assigned to different layers. The first light source unit uses visible light optimized for surface defect detection in the first layer, while the second light source unit uses infrared light with specific penetration characteristics for detecting buried defects in the second layer, achieving precise defect depth differentiation through localized light source optimization
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 achieves improved consistency in defect inspection by enabling accurate differentiation between surface and buried defects, enhancing the precision of semiconductor manufacturing processes.
Implementation Method 1
a beam splitter configured to reflect the first incident light and the second incident light from the first light source to the measurement target, and transmit first reflected light and second reflected light therethrough
Implementation Method 2
transmit first reflected light and second reflected light therethrough
Implementation Method 3
an objective lens disposed between the beam splitter and the measurement target
Implementation Method 4
a detector configured to: detect the first reflected light and generate a first image of the first layer based on the detected first reflected light; and detect the second reflected light and generate a second image of the second layer
Data Source
AI summary
A defect inspection system includes a stage configured to receive a measurement target thereon, wherein the measurement target includes a first layer and a second layer disposed under the first layer; and a defect inspection apparatus including: a light source unit configured to output first incident light and second incident light; a beam splitter configured to reflect the first incident light and the second incident light from the first light source to the measurement target, and transmit first reflected light and second reflected light therethrough, wherein the first reflected light corresponds to the first incident light reflected from the first layer and the second reflected light corresponds to the second incident light reflected from the second layer; an objective lens disposed between the beam splitter and the measurement target; and a detector configured to: detect the first reflected light and generate a first image of the first layer based on the detected first reflected light; and detect the second reflected light and generate a second image of the second layer based on the detected second reflected light, wherein the first incident light is included in a visible light band, and wherein the second incident light is included in an infrared light band.