Dual-Sided Alignment Marks for Display Substrate Overlay Accuracy
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Solution Overview
Problem
In the manufacturing of display substrates, achieving accurate alignment between the front and back surfaces is challenging due to process variations, which affects signal connectivity and bezel reduction in display devices.
Innovation Solution
An alignment mark system is introduced, comprising a first alignment marker on the front surface and a second alignment marker on the back surface, with specific patterns and displacement value markers to represent process variations, allowing for direct observation and correction of alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional alignment methods are used without specific alignment markers, then the manufacturing process is simpler, but the alignment precision between front and back surfaces deteriorates
Solution Approach 1:
The patent introduces alignment markers as intermediary elements that mediate between the front and back surfaces of the substrate. These markers serve as reference points that enable precise alignment measurement and correction without requiring complex direct measurement systems between the two surfaces.
Solution Approach 2:
The alignment markers are formed by copying patterns from the front surface to the back surface through the substrate. This copying process creates corresponding reference points on both surfaces that can be used to detect and correct alignment variations, thereby improving alignment precision while maintaining a relatively simple manufacturing process.
2Measurement precision
If alignment markers are introduced to detect process variations, then the alignment accuracy improves, but the manufacturing process complexity increases
Solution Approach 1:
The alignment mark system is segmented into multiple functional components: first alignment markers on the front surface, second alignment markers on the back surface, and displacement value markers for measurement. This segmentation allows each component to perform its specific function efficiently, improving measurement precision while keeping the overall system manageable.
Solution Approach 2:
The patent utilizes different visual characteristics (analogous to color changes) of the alignment markers to represent different alignment states and process variations. The displacement value markers provide visual feedback about alignment accuracy, enabling precise measurement without requiring complex electronic measurement systems.
3Reliability
If accurate alignment is achieved through process correction, then signal connectivity improves, but the correction process time increases
Solution Approach 1:
The alignment markers are formed in advance during the substrate manufacturing process, before the actual alignment and assembly operations. This preliminary action allows for pre-detection of alignment variations and enables corrective measures to be planned and executed more efficiently, reducing the time required for alignment correction while ensuring reliable signal connectivity.
Data Source
AI summary
An alignment mark includes a first alignment marker located on a first surface of a substrate and a second alignment marker located on a second surface of the substrate. The second alignment marker is arranged to be matched with the first alignment marker, and capable of representing a process variation between the second alignment marker and the first alignment marker.