Dual-Sided Wafer Imaging Apparatus for Defect Detection
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Solution Overview
Problem
The semiconductor industry faces challenges in efficiently inspecting wafers for defects due to foreign particle contamination and occlusions on the backside, which are costly and time-consuming for human inspection, and require optimized dual-sided wafer imaging and inspection processes.
Innovation Solution
A dual-sided wafer imaging apparatus and method utilizing one or more load ports, mechanical arms, a wafer transfer stage, line scan cameras, optical lenses, and air injection devices to capture and process dual-sided images of wafers, with deep learning object detection for defect classification, and automated alignment to prevent particle adherence and improve image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If human inspection is used for wafer defect detection, then inspection flexibility is maintained, but inspection cost and time consumption increase significantly
Solution Approach 1:
The patent replaces manual mechanical inspection with an automated optical imaging system comprising cameras, lenses, and light sources. The system captures wafer images automatically and uses image processing algorithms to detect defects, eliminating the need for human inspectors while significantly improving inspection speed and consistency.
Solution Approach 2:
The imaging system is designed to operate autonomously within the semiconductor manufacturing process. The wafer is automatically transferred to the imaging stage, imaged from multiple sides, and analyzed for defects without requiring external human intervention at each step, enabling continuous high-speed inspection.
2Measurement precision
If single-sided wafer imaging is performed, then device complexity is reduced, but backside wafer images are occluded by contact points and particles
Solution Approach 1:
The imaging system is divided into separate imaging modules for the front side and back side of the wafer. Each side has its own camera, lens, and light source configuration. This segmentation allows independent optimization of each imaging path and enables comprehensive defect detection on both wafer surfaces without mutual interference.
Solution Approach 2:
The system transitions from single-sided (one-dimensional inspection) to dual-sided (two-dimensional inspection) wafer imaging. By adding the capability to image both the front and back sides of the wafer, the system eliminates occlusion problems that affect single-sided imaging and provides complete defect coverage.
3Measurement precision
If dual-sided wafer imaging is implemented, then imaging completeness is improved, but particle adherence to optical lenses increases
Solution Approach 1:
The system performs preliminary imaging of the wafer back side before the wafer makes contact with the support structure that could generate particles. By capturing the image in advance, the system avoids particle contamination that would occur during subsequent handling and positioning operations.
Solution Approach 2:
The patent introduces an intermediary transfer mechanism that minimizes direct contact between the wafer and potential contamination sources. The wafer is transferred through a controlled environment with reduced particle generation, protecting the optical lenses from particle adherence while maintaining imaging capability.
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 solution significantly reduces errors and costs associated with human inspection, enables accurate non-occluded backside imaging, and facilitates rapid defect data collection and analysis using artificial intelligence.
Implementation Method 1
The air injection device injects an air stream to prevent particles from adhering to the first optical lens and the second optical lens
Implementation Method 2
The wafer transfer stage comprises three or more vacuum suction points in contact with a backside of the wafer
Data Source
AI summary
The present disclosure provides a dual-sided wafer imaging apparatus and methods thereof. The dual-sided wafer imaging apparatus includes one or more load ports, one or more mechanical arms for transporting a wafer, a wafer transfer stage, a first line scan camera mounted below the wafer transfer stage, a second line scan camera mounted above the wafer transfer stage, a first optical lens mounted on the first line scan camera, a second optical lens mounted on the second line scan camera, and line light sources respectively mounted below and above the wafer transfer stage. The load ports are configured for an automated load operation or unload operation of a wafer pod of an automated transport equipment. The wafer transfer stage includes vacuum suction points in contact with a backside of the wafer, and the wafer transfer stage further includes a drive motor producing a linear reciprocating motion for moving the wafer.