Wafer Imaging Black Box for Reflective Surface Defect Detection
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Solution Overview
Problem
Current semiconductor wafer imaging systems struggle to effectively image reflective, mirror-like surfaces due to the need for diffuse light and the large size of parabolic mirrors, which limits their placement in manufacturing processes and increases costs by often requiring the removal of defective wafers post-cleaving.
Innovation Solution
A semiconductor wafer imaging system featuring a black box with shroud panels and a camera that uses diffuse light from an illumination panel to image wafers without reflecting the light source, allowing for defect detection and minimizing reflections, thus reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If diffuse light is used to image reflective wafer surfaces, then accurate defect detection is achieved, but the imaging system requires large parabolic mirrors that increase system size and limit placement options
Solution Approach 1:
A black body cavity (intermediary structure) is introduced between the light source and the wafer surface. This cavity diffuses the light before it reaches the wafer, eliminating the need for large parabolic mirrors while still achieving accurate defect detection on reflective surfaces. The cavity acts as a mediator that transforms direct light into diffuse light without requiring bulky optical components.
Solution Approach 2:
The patent extracts the light-diffusing function from the large parabolic mirror system and relocates it to a compact black body cavity structure. This separation allows the imaging system to maintain defect detection accuracy while dramatically reducing the overall system volume and enabling flexible placement within manufacturing lines.
2Measurement precision
If large parabolic mirrors are used in the imaging system, then reflective surfaces can be imaged accurately, but the system size increases and disrupts the manufacturing process flow
Solution Approach 1:
The black body cavity serves as an intermediary that provides the necessary light diffusion for accurate surface imaging while occupying minimal space. This allows the imaging system to be integrated into the manufacturing process without disrupting workflow or requiring extensive reconfiguration of the production line.
Solution Approach 2:
The patent transitions from a two-dimensional mirror-based light diffusion approach to a three-dimensional cavity structure that achieves diffusion through volumetric geometry. This dimensional change enables compact packaging of the imaging system, allowing it to fit within the constrained spaces of modern manufacturing equipment without compromising imaging accuracy.
3Device complexity
If the camera images the light source directly, then the imaging system is simpler, but the reflected image shows the light source instead of wafer features
Solution Approach 1:
The black body cavity acts as an intermediary that diffuses light before it reaches the wafer, ensuring that the camera captures only the wafer surface features and not the light source. This mediator structure prevents direct line-of-sight between the light source and camera while still providing sufficient illumination for high-quality imaging.
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
Enables efficient imaging of semiconductor wafers after processing, including cleaving, by using diffuse light to detect defects without imaging the light source, thereby reducing waste and lowering production costs.
Implementation Method 1
A portion of the diffuse light is reflected off the semiconductor wafer and the camera images the semiconductor wafer by detecting the reflected diffuse light
Data Source
AI summary
A semiconductor wafer imaging system for imaging a semiconductor wafer includes shroud panels defining a black box, a camera positioned in the black box for imaging the semiconductor wafer, and an illumination panel for directing diffuse light to the semiconductor wafer. A portion of the diffuse light is reflected off the semiconductor wafer and the camera images the semiconductor wafer by detecting the reflected diffuse light.