Substrate Flatness Inspection via Multi-Point Line Measurement
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Solution Overview
Problem
Current display panel manufacturing processes face challenges in achieving high-resolution outputs due to the need for significantly flat metal masks, which are difficult to manufacture with existing inspection methods, resulting in low yields.
Innovation Solution
A method for inspecting the flatness of substrates involves selecting multiple inspecting points along straight lines on the substrate surface, calculating a flatness index using specific formulas, and determining substrate quality based on threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional inspection methods are used for substrate flatness, then the inspection process is simple, but the manufacturing precision of metal masks deteriorates, resulting in low yields
Solution Approach 1:
The inspection method segments the substrate surface into multiple measurement lines, with each line containing multiple inspecting points. By dividing the complex flatness inspection into multiple one-dimensional measurements along different directions, the method achieves comprehensive flatness evaluation without requiring an overly complex three-dimensional measurement system.
Solution Approach 2:
The patent transitions from simple point-to-point measurement to measuring along multiple straight lines in different directions (first direction and second direction perpendicular to the first). This multi-dimensional approach captures the substrate flatness more comprehensively, transforming a single-dimension inspection into a multi-dimensional evaluation that better assesses overall flatness.
2Measurement precision
If more inspecting points and measurement lines are used, then the flatness inspection accuracy is improved, but the inspection time and complexity increase
Solution Approach 1:
The method establishes a systematic framework in advance by defining multiple measurement lines in different directions and pre-determining the inspecting points along each line. This preliminary planning allows for efficient execution during actual inspection, reducing time consumption while maintaining high measurement precision through the structured approach.
3Productivity
If substrates with poor flatness are used for metal mask manufacturing, then the manufacturing process can proceed, but the display panel resolution deteriorates
Solution Approach 1:
The inspection method is applied as a preliminary screening process before metal mask manufacturing. By measuring multiple straight lines in different directions and calculating flatness indices in advance, the method identifies and filters out substrates with poor flatness before they enter the manufacturing process, ensuring that only qualified substrates are used to maintain high display panel resolution.
Solution Approach 2:
The method calculates flatness indices based on measurement data and uses these indices to determine whether substrates meet the required flatness standards. This feedback mechanism allows for real-time quality control, ensuring that only substrates with sufficient flatness (flatness index within acceptable range) are selected for manufacturing, thereby maintaining high resolution while ensuring productivity.
Data Source
AI summary
A method of inspecting flatness of substrate is provided and includes providing a substrate. N first inspecting points are selected from the surface of the substrate along a first straight line, where the coordinate of the i-th first inspecting point is (Xi,Yi,Zi). By using a formula“D=∑ i=1N-1(Xi+1-Xi)2+(Yi+1-Yi)2+(Zi+1-Zi)2”,a first measurement length D is calculated. By using a formula “F=(D−S)/S”, a first flatness index F is calculated. S is the horizontal distance between 1st first inspecting point and N-th first inspecting point. When the first flatness index F is larger than a first threshold, the substrate is determined to be unqualified.