Single Camera Semiconductor Wafer Inspection System
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Solution Overview
Problem
Current semiconductor inspection systems require multiple expensive cameras to image semiconductor wafers at multiple wavelengths and angles, leading to high manufacturing costs and reliability issues due to the risk of failure from multiple cameras.
Innovation Solution
A method and apparatus that utilize a single camera to capture images of semiconductor wafers illuminated by multiple wavelengths and at multiple angles, reducing the number of cameras needed by using multiple illuminators operating at different wavelengths or angles, and synchronizing the imaging device to capture separate images for analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple cameras are used to image semiconductor wafers at multiple wavelengths and angles, then imaging capability is improved, but manufacturing cost increases
Solution Approach 1:
A single camera is designed to perform multiple imaging functions by capturing images at different wavelengths and angles through coordinated illumination from multiple illuminators. The camera serves as a universal imaging device that replaces what would traditionally require multiple specialized cameras, thereby reducing manufacturing costs while maintaining comprehensive imaging capability.
Solution Approach 2:
Multiple illuminators operate at different wavelengths and angles in alternating periodic sequences, with each illuminator illuminating the wafer at discrete intervals. The single camera captures images during these periodic illumination events, enabling multi-wavelength and multi-angle imaging through time-sequential capture rather than requiring simultaneous multi-camera operation.
2Adaptability or versatility
If multiple cameras are used to image semiconductor wafers, then imaging capability is improved, but reliability deteriorates
Solution Approach 1:
By designing a single camera to perform multiple imaging functions across different wavelengths and angles, the system eliminates the reliability risks associated with multiple cameras. The universal camera approach ensures that only one critical imaging component needs to function properly, thereby significantly improving system reliability while maintaining comprehensive imaging capability through coordinated multi-illuminator operation.
3Measurement precision
If multiple cameras are used to capture multiple images, then inspection thoroughness is improved, but device complexity increases
Solution Approach 1:
Multiple illuminators operate in periodic sequences at different wavelengths and angles, with each illuminator activating at discrete intervals. The single camera captures images during these periodic illumination events, enabling comprehensive inspection through time-sequential multi-wavelength and multi-angle imaging without requiring multiple simultaneous cameras, thereby reducing device complexity while maintaining inspection thoroughness.
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 reduces the number of cameras required, lowers manufacturing costs, enhances reliability, and allows for more efficient defect detection, including micro-cracks and photoluminescence features, while maintaining superior resolution with line cameras.
Implementation Method 1
two or more illuminators operating at different wavelengths illuminate a semiconductor wafer
Implementation Method 2
images of the illuminated semiconductor wafer are captured by a camera. The images may be optical images (transmitted, reflected, or scattered) at the same wavelength of the illuminator or photoluminescence images at a different wavelength from the illumination wavelength
Data Source
AI summary
A semiconductor wafer inspection system includes a camera and two or more illuminators. The illuminators illuminate a line of the semiconductor wafer in sequence and the camera captures an interleaved image of illuminated lines such that the individual images can be recovered from the interleaved image. The semiconductor wafer can be moved by a conveyor so that adjacent lines can be sequentially illuminated by the illuminators. The camera may include two or more line sensors.