Substrate Alignment via Optical Corner Detection
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Solution Overview
Problem
Existing substrate handling technologies face challenges in accurately aligning non-square or polygonal substrates without touching their sensitive edges, leading to potential damage and requiring additional process steps for edge inspection.
Innovation Solution
A method and device that use a substrate holder movable in the XYZ directions and rotatable about the Z axis, combined with an image detection system, to determine and adjust the position and orientation of polygonal substrates during transport, allowing for edge inspection without physical contact and eliminating the need for additional handling steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate holder touches the substrate edge for alignment, then the alignment precision is improved, but the substrate edge may be damaged
Solution Approach 1:
The patent uses an optical field (image recording device) as an intermediary to detect substrate position and orientation without physical contact. The image recording device captures substrate images, and the evaluation device processes these images to determine precise alignment parameters, replacing direct mechanical contact with optical measurement.
Solution Approach 2:
The patent replaces the mechanical contact-based alignment system with an optical measurement and computational alignment system. Instead of using mechanical fixtures to physically align the substrate, the system uses image capture, coordinate transformation algorithms, and robotic positioning to achieve precise alignment without mechanical contact.
2Reliability
If additional process steps are added for edge inspection, then the quality control is improved, but the process complexity increases
Solution Approach 1:
The patent merges the alignment function and quality inspection function into a single integrated process. The image recording device serves dual purposes: capturing substrate images for alignment calculation and simultaneously enabling edge inspection. The evaluation device performs both alignment parameter calculation and quality assessment without requiring separate inspection steps.
Solution Approach 2:
The image recording device and evaluation device are designed with multi-functionality, serving both alignment determination and edge quality inspection purposes. This universal approach allows the same hardware to perform multiple functions, eliminating the need for separate dedicated inspection equipment and process steps.
3Reliability
If the substrate is rotated multiple times for inspection, then the edge inspection completeness is improved, but the processing time increases
Solution Approach 1:
The patent performs preliminary action by capturing a complete substrate image that includes all edges and corners in a single shot. The image recording device is positioned and configured to capture the entire substrate perimeter, eliminating the need for multiple rotation and capture cycles. The evaluation device then processes this single comprehensive image to inspect all edges.
Solution Approach 2:
The patent transitions from a temporal sequence of multiple rotations and captures to a spatial solution where all edges are captured simultaneously in a single two-dimensional image. By utilizing the spatial arrangement of the image recording device to capture the entire substrate perimeter at once, the system eliminates the time-consuming sequential rotation process.
Data Source
Figure 1
Figure 2a~2b
AI summary
The invention relates to a method and a device for aligning substrates (2) in an X-Y plane. A polygonal, flat substrate (2), the substrate plane of which is parallel to the X-Y plane or lies in the X-Y plane, is aligned with respect to reference coordinates and a reference angular position. A corner (12) of the substrate (2) is detected using an image recording device (9). In addition, the position coordinates of the substrate (2) are determined. Using an evaluating device (10), the angular position of the corner (12) of the substrate (2) in the X-Y plane is determined, and the position differences between the reference coordinates and the position coordinates and the angle difference between the reference angular position and the angular position of the substrate corner (12) are calculated. The substrate (2) is moved and/or rotated in the X-Y plane according to the determined position difference or the angle difference. By rotating the substrate (2) several times, each corner (12) and edge (13, 14) of the substrate (2) can be detected using the image recording device (9). This enables an edge inspection during the substrate transport so that additional process steps such as laying the substrate (2) down and picking the substrate back up can be omitted.