Large Thin-Film Transistor Substrate via Segmented Photo-Mask Exposure
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Solution Overview
Problem
The manufacturing process of large-size thin-film transistor substrates faces challenges due to the difficulty in producing large-size photo-masks, which increases costs and complexity, as existing methods struggle to efficiently create patterns on larger substrates.
Innovation Solution
A method utilizing a photo-mask with specific exposure areas, peripheral line patterns, dummy line patterns, and overlapping pixel patterns to unify patterns through multi-exposure processes, allowing for the efficient manufacturing of large-size thin-film transistor substrates by forming a patterned photoresist layer that can be used as an etch mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of the thin film transistor substrate is increased, then the display area and productivity are improved, but the manufacturing difficulty and cost increase dramatically
Solution Approach 1:
The photo-mask is divided into multiple separate masks (first photo-mask, second photo-mask, third photo-mask) that can be manufactured independently using conventional techniques. Each mask covers a specific region (first exposure area, second exposure area, third exposure area) and contains specific patterns (peripheral line patterns, dummy line patterns, overlapping pixel patterns). These segmented masks are then used in sequence during multiple exposure processes to collectively form the complete pattern on the large substrate, thereby enabling large substrate manufacturing without requiring a single large photo-mask.
2Area of stationary object
If the size of the photo-mask is increased to match the substrate size, then the pattern coverage is improved, but the manufacturing cost and difficulty increase dramatically
Solution Approach 1:
Instead of manufacturing one large photo-mask that covers the entire substrate area, the patent segments the photo-mask into multiple smaller masks (first photo-mask, second photo-mask, third photo-mask). Each smaller mask can be manufactured using conventional photo-mask fabrication techniques without requiring large-scale manufacturing capabilities. The segmented masks are then used in multiple exposure steps to collectively cover the entire substrate area, thereby achieving full coverage without the need for expensive and difficult large photo-mask manufacturing.
Solution Approach 2:
The patent transitions from a single-plane exposure approach to a multi-plane, multi-step exposure approach. By using multiple smaller photo-masks that are sequentially applied to different regions or layers of the substrate through multiple exposure processes, the system achieves comprehensive pattern coverage in a dimensional sense (across multiple exposure steps and regions) without requiring any single mask to be physically large.
3Area of stationary object
If multiple exposure processes are used to cover the entire substrate, then the pattern completeness is improved, but the alignment accuracy and process complexity increase
Solution Approach 1:
Each photo-mask is designed with specific local patterns tailored to its designated exposure area: the first photo-mask contains peripheral line patterns and dummy line patterns for the first exposure area, the second photo-mask contains overlapping pixel patterns for the second exposure area, and the third photo-mask contains complementary overlapping pixel patterns for the third exposure area. These locally-optimized patterns ensure that each exposure step contributes appropriately to the final complete pattern, with the overlapping regions providing alignment reference and ensuring pattern unity across multiple exposures.
Solution Approach 2:
The dummy line patterns and overlapping pixel patterns serve as intermediary elements that facilitate alignment between multiple exposure steps. The dummy line patterns provide reference structures for alignment, while the overlapping pixel patterns in the second and third exposure areas create complementary patterns that, when overlaid, unify to form the complete pixel pattern. These intermediary patterns act as alignment markers and pattern unifiers that enable accurate registration across multiple exposure processes.
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 approach enables the production of large-size thin-film transistor substrates with reduced manufacturing costs and complexity, allowing for increased substrate size without size limitations on the photo-mask, while maintaining pattern accuracy and luminance uniformity.
Implementation Method 1
The pattern of a photo-mask is transformed to a photoresist layer of the substrate through several exposure processes for forming a patterned photoresist layer
Data Source
AI summary
A photo-mask having a first exposure area, a second exposure area and a third exposure area is for manufacturing a thin-film transistor substrate. The photo-mask includes a first peripheral line pattern, a first dummy line pattern, a first overlapping pixel pattern and a second overlapping pixel pattern. The first peripheral line pattern is in the first exposure area. The first dummy line pattern is in the first exposure area and connected to the first peripheral line pattern. The first overlapping pixel pattern is in the first exposure area and connected to the first dummy line pattern. The first overlapping pixel pattern is complementary to the second overlapping pixel pattern in the second exposure area. After exposing through and overlapping the first and second overlapping pixel patterns, two patterns respectively formed from exposing through the first and second exposure area are unified.