In-line Optical Inspection for Display Substrate Alignment
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Solution Overview
Problem
The challenge in the display manufacturing industry is to effectively scan and control substrate integrity and alignment, particularly with shrinking pixel sizes and fast refresh rates, which leads to issues like glass breakage and increased maintenance costs due to defective substrates and misalignments.
Innovation Solution
A processing device and method that utilize high-speed optical devices and radiation sources positioned above the substrate to capture images and deliver radiation simultaneously, allowing for real-time inspection of substrate edges and alignment, enabling the detection of defects and misalignments, and adjusting or stopping the process if variance exceeds acceptable limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional inspection methods are used, then inspection cost is reduced, but inspection speed and precision deteriorate leading to accumulation of defective substrates
Solution Approach 1:
The patent combines multiple inspection functions (edge inspection, alignment check, defect detection) into a single integrated optical inspection system. The system uses a camera and light source assembly that simultaneously captures substrate edge position, alignment, and defects in one inspection pass, resolving the contradiction by merging multiple measurement tasks into one high-speed operation.
Solution Approach 2:
The patent replaces traditional mechanical contact-based inspection methods with non-contact optical inspection using cameras and light sources. This substitution enables high-speed inspection without physical contact, maintaining precision while dramatically increasing inspection speed and preventing substrate damage.
2Manufacturing precision
If glass thickness is reduced to achieve smaller pixel sizes, then display resolution is improved, but glass breakage risk increases
Solution Approach 1:
The patent performs preliminary inspection of substrate edges and alignment before the thin glass substrate enters the processing chamber. By detecting potential defects, cracks, or misalignments in advance, the system prevents defective substrates from undergoing processing that could cause breakage, thus protecting the thin glass while maintaining manufacturing precision.
Solution Approach 2:
The inspection system provides real-time feedback on substrate quality and alignment status. This feedback mechanism allows the system to identify and flag substrates with defects or misalignments before processing, enabling preventive action to avoid glass breakage while maintaining the ability to produce high-resolution displays with reduced thickness.
3Measurement precision
If comprehensive substrate inspection is performed, then defect detection accuracy is improved, but inspection time increases reducing production efficiency
Solution Approach 1:
The patent implements continuous inspection as substrates move through the system on the transfer rack. The optical inspection system operates continuously without stopping substrate transport, capturing images and analyzing defects in real-time. This continuous operation maintains high detection accuracy while minimizing inspection time and maintaining production efficiency.
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 enables rapid and accurate inspection of substrate integrity and alignment, reducing the likelihood of glass breakage and maintenance downtime by preventing defective substrates from entering the processing chamber and ensuring precise alignment of deposited layers, thus maintaining production efficiency and quality.
Implementation Method 1
a radiation source positioned outside of the opening to deliver radiation to the lateral edges of the substrate
Implementation Method 2
at least two optical devices positioned to view the lateral edges of the substrate... such that radiation is delivered to the lateral edges of the substrate at approximately the same time that the optical device captures a plurality of images
Data Source
AI summary
Methods and apparatus for determining substrate integrity and alignment are described. Devices as described herein can include a transfer chamber, one or more process chambers, a loadlock chamber a first optical device, a second optical device and a radiation source positioned outside and above an opening for the loadlock chamber. Methods as described herein can include delivering a substrate to an opening in a process chamber, activating the optical device and the radiation source and capturing a plurality of images, extracting a substrate edge pattern from the plurality of images, comparing the substrate edge pattern to an expected edge pattern to determine a level of edge variance and adjusting or stopping a process if the level of edge variance is outside of an edge variation range.