Alignment Mark Structure for Mask Misalignment Correction
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Solution Overview
Problem
In the manufacturing of large flat panel displays, accurately measuring and correcting misalignment of masks during the sequential alignment process is challenging due to the limited size of pattern masks, which can lead to failures in layer formation and structural defects.
Innovation Solution
A display device with alignment marks that include a quadrangular-shaped center portion and surrounding measurement portions, allowing for the accurate measurement of mask misalignment by comparing distances between these features, which are formed simultaneously with the patterning process using multiple masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If sequential mask alignment is used for large display devices, then the display device can be manufactured with larger size, but mask misalignment occurs leading to manufacturing precision degradation
Solution Approach 1:
Alignment marks are formed in advance on the substrate before the actual patterning process. These pre-formed marks serve as reference points that enable precise measurement and correction of mask alignment during sequential exposure, thus maintaining manufacturing precision while allowing larger display device sizes
Solution Approach 2:
The alignment marks act as an intermediary element between the mask and the substrate. By providing measurable reference features, they mediate the alignment process and enable detection of positional deviations, allowing for correction of mask misalignment without compromising the final patterning precision
2Adaptability or versatility
If multiple masks are used for patterning, then complex patterns can be formed, but alignment measurement becomes difficult leading to detection difficulty
Solution Approach 1:
Alignment marks serve as intermediary reference features that simplify the measurement process. Instead of directly measuring complex pattern alignments, the system uses these simple, well-defined marks as intermediaries to detect mask positions and calculate alignment errors, making detection straightforward even when multiple masks are involved
Solution Approach 2:
The alignment marks utilize contrasting materials (such as light-blocking and light-transmitting regions) that create distinct visual or optical signals. This contrast enables easy detection and measurement of mark positions, facilitating accurate alignment measurement despite the complexity of multiple mask patterning steps
Data Source
AI summary
A method of manufacturing a display device including: preparing a substrate having a display area and a non-display area; and forming an alignment mark disposed in the non-display area of the substrate. The alignment mark includes a quadrangular-shaped center portion and a plurality of measurement portions that surround the center portion, the plurality of measurement portions including four or more measurement portions, and each of the measurement portions including sides that are parallel with two sides of the quadrangular-shaped center portion.