Array Substrate Carbon Film Patterning for Fewer Photomasks
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Solution Overview
Problem
The miniaturization of light-emitting diode (LED) backplane manufacturing processes require multiple photomasks for patterning the passivation and black organic photoresist layers, making the process complex and costly.
Innovation Solution
A method involving the formation of a full-surface carbon film on the passivation layer, which is then patterned using plasma to remove the carbon film and passivation layer corresponding to the conductive pad, reducing the need for multiple photomasks by using the carbon film as a light-shielding layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple photomasks are used for patterning the passivation layer and black organic photoresist layer, then the manufacturing precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the passivation layer and black organic photoresist layer into a single integrated structure. The passivation layer itself is patterned to directly define both the transistor protection areas and the black matrix positions, eliminating the need for separate photomasks for each layer. This merging approach maintains patterning precision while significantly reducing process complexity.
Solution Approach 2:
The patterned passivation layer serves multiple functions simultaneously: it protects the thin film transistor, defines the conductive pad boundaries, and creates the black matrix structure for light absorption. This multi-functionality allows a single patterning process to achieve what previously required multiple separate photomasks, reducing device complexity while maintaining manufacturing precision.
2Manufacturing precision
If multiple photomasks are used for patterning, then the manufacturing precision is improved, but the productivity decreases
Solution Approach 1:
By merging the passivation and black matrix patterning into a single photomask process, the manufacturing cycle is shortened. Instead of applying and processing multiple photoresist layers with separate photomasks, the invention uses one photomask to define both features, directly improving productivity while preserving patterning precision through the integrated design.
Solution Approach 2:
The passivation layer is designed and patterned in advance to simultaneously serve as the black matrix definition layer. This preliminary action of creating a multi-functional passivation structure eliminates the need for subsequent separate black matrix patterning steps, thereby increasing manufacturing efficiency without sacrificing precision.
3Manufacturing precision
If multiple photomasks are used for patterning, then the manufacturing precision is improved, but the manufacturing cost increases
Solution Approach 1:
The invention merges multiple patterning functions into a single photomask, directly reducing the cost of photomask fabrication, storage, and handling. The integrated passivation layer design allows one photomask to define both transistor protection and black matrix regions, eliminating the need for expensive multiple photomasks while maintaining the precision required for mini-LED backlight manufacturing.
Solution Approach 2:
The patterned passivation layer performs multiple functions (transistor protection, pad definition, and black matrix formation) that previously required separate processing steps and additional photomasks. This universality reduces material costs, process complexity, and overall manufacturing expense while preserving the precision needed for high-quality mini-LED displays.
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 by reducing the number of photomasks required, lowering costs and improving efficiency in producing mini-LED backplanes with high contrast and color rendering performance.
Implementation Method 1
removing the carbon film corresponding to the conductive pad using plasma to react with the carbon film not covered by the patterned photoresist layer
Implementation Method 2
sputtering graphite as a target material on the passivation layer to form the full-surface carbon film
Data Source
AI summary
An array substrate, a method for fabricating the same, and a display device are provided. The method includes: forming a passivation layer on an array substrate, wherein the array substrate includes a thin film transistor and a conductive pad, and the passivation layer covers the thin film transistor and the conductive pad; forming a full-surface carbon film on the passivation layer; and patterning the carbon film and the passivation layer to remove the passivation layer and the carbon film corresponding to the conductive pad by a patterning process to obtain the array substrate.