Display Backside Metal Patterning for Precise Alignment
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Solution Overview
Problem
The double-sided process of manufacturing display devices, particularly OLED and micro-LED displays, is complicated due to the need for multiple layers and alignment processes, including vacuum film formation and photomask patterning, which increases time and production costs.
Innovation Solution
A method involving two patterning processes to form a metal member on the second surface of the thin-film transistor array substrate, using edge exposure and photomask alignment to reduce the complexity and cost by omitting non-metal layers and photomasks, and forming a planarization layer to improve alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transparent non-metallic film is formed on the back side for alignment marks, then alignment accuracy is improved, but the manufacturing process becomes more complicated due to multiple steps including vacuum film formation, photomask patterning, and etching
Solution Approach 1:
The patent extracts and eliminates the transparent non-metallic film layer and its associated complex manufacturing steps (vacuum film formation, photomask patterning, etching) from the back side process. Instead, it uses the substrate's own reflective properties with simple grayscale marks that can be directly observed during alignment, thereby maintaining alignment accuracy while removing unnecessary process complexity
Solution Approach 2:
The patent replaces the expensive and complex transparent non-metallic film structure with simple grayscale marks formed directly on the substrate. These marks serve their alignment purpose effectively without requiring additional material layers or complex fabrication steps, essentially using a simpler, more economical approach that achieves the same functional goal
2Measurement precision
If a layer of metal is added to cover the non-metallic film mark, then mark recognition ability is improved, but the manufacturing steps become more complicated
Solution Approach 1:
The patent removes the metal layer covering step entirely from the manufacturing process. Instead of adding metal to enhance mark visibility, it utilizes the substrate's natural reflectivity and employs grayscale marks with optimized contrast that can be clearly recognized during alignment without any additional metal deposition or patterning steps
Solution Approach 2:
The substrate itself serves the dual purpose of structural support and alignment mark carrier. The substrate's inherent reflective properties are leveraged to provide sufficient contrast for mark recognition, eliminating the need for additional metal layers that would otherwise be required to enhance visibility
3Manufacturing precision
If accurate alignment with marks is performed on the back side, then manufacturing precision is improved, but production time increases due to multiple processes including alignment and cutting
Solution Approach 1:
The patent performs alignment mark formation and optimization during the substrate fabrication stage itself, before the back side processing begins. The grayscale marks are integrated into the substrate structure in advance, so that during back side processing, alignment can be performed quickly and directly without needing to first create or prepare separate alignment marker structures
Solution Approach 2:
The patent eliminates multiple time-consuming processes including separate alignment mark fabrication, photomask alignment, and cutting steps. By using simple grayscale marks that can be directly observed on the substrate surface, it streamlines the back side process to focus only on the essential alignment and bonding operations
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 simplifies the manufacturing process, reduces time and production costs, and enhances alignment accuracy, enabling more efficient production of seamless and borderless display devices.
Implementation Method 1
exposing the first photoresist layer at a first predetermined position by edge exposure
Implementation Method 2
etching the metal film at the first predetermined position
Implementation Method 3
exposing the second photoresist layer at a second predetermined position with a photomask
Implementation Method 4
etching the metal layer at the second predetermined position to form the metal member
Data Source
AI summary
The present invention discloses a display device and a manufacturing method thereof, including the following steps: forming a thin-film transistor array substrate, the thin-film transistor array substrate including a first surface and a second surface that are disposed opposite to each other; forming a protective layer on the first surface; forming a metal layer on the second surface by a first patterning; forming a metal member by performing a second patterning on the metal layer; forming a patterned insulating layer on the second surface; forming an electrode layer on the metal member; forming a planarization layer on the electrode layer and the insulating layer; and removing the protective layer.