Wafer Mapping Vision System for Warped Substrate Handling
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Solution Overview
Problem
Existing substrate mapping techniques in semiconductor fabrication equipment, such as vacuum-suction and break-beam methods, are inefficient and complex, leading to reduced throughput and increased manufacturing costs due to false readings, mechanical complexity, and difficulty in handling substrates with varied thicknesses and warping.
Innovation Solution
A substrate mapping apparatus using a machine vision system with cameras and illuminators to capture and process images of substrate stacks, determining edge profiles and adjusting end effector tines to accommodate warped substrates, eliminating moving parts and enhancing mapping accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scribe is used to manually map substrate positions, then mapping can be performed, but time is lost and precision is reduced due to human error
Solution Approach 1:
The patent replaces manual mechanical scribing with an automated imaging system using cameras to capture substrate positions. The system uses optical fields instead of mechanical contact to detect and record substrate locations, eliminating human error and time loss while maintaining high precision through automated coordinate mapping.
2Area of stationary object
If multiple reticles are used to cover a large area, then the measurable area increases, but alignment precision deteriorates due to cumulative errors
Solution Approach 1:
The patent divides the large-area measurement task into multiple overlapping image captures taken from different positions. Each capture covers a portion of the substrate array, and the system automatically stitches these segments together with precise coordinate transformation, avoiding cumulative alignment errors that would occur with physical reticle stacking.
Solution Approach 2:
The patent introduces a coordinate system and image processing algorithms as intermediaries to bridge multiple measurement areas. Instead of physically aligning multiple reticles, the system uses digital coordinate transformation to accurately map positions across the entire substrate array, eliminating physical alignment errors.
3Device complexity
If manual scribing is used for mapping, then equipment complexity is reduced, but reliability decreases due to human error
Solution Approach 1:
The patent implements self-service automation where the imaging system automatically captures images, processes coordinates, and generates position maps without human intervention. The system performs self-calibration and self-correction, eliminating human error while maintaining reasonable equipment complexity through integrated software-hardware solutions.
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
Improves substrate handling efficiency by reducing mechanical complexity, minimizing false readings, and adapting to varied substrate thicknesses and warping, thereby increasing throughput and reducing manufacturing costs.
Implementation Method 1
The at least one illuminator is configured so as to illuminate an outer edge of each substrate S held in the substrate carrier C and the image captured of the separate different part by each respective camera optimally defines the outer edge of the substrate S by reflecting edge illumination from the at least one illuminator at the camera, and by optically blanking background reflection light, viewed by each camera, in the image captured
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A semiconductor wafer mapping apparatus comprising a frame forming a wafer load opening communicating with a load station for a substrate carrier disposed to hold more than one wafers vertically distributed in the substrate carrier for loading through the wafer load opening, a movable arm movably mounted to the frame so as to move relative to the wafer load opening and having at least one end effector movably mounted to the movable arm to load wafers from the substrate carrier through the wafer load opening, an image acquisition system including an array of cameras arranged on a common support and each camera fixed with respect to the common support that is static with respect to each camera of the array of cameras, wherein each respective camera is positioned with a field of view disposed to view through the wafer load opening with the common support positioned by the movable arm.