TFT Conductive Stack Layer for Low Impedance Signal Transmission
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Solution Overview
Problem
Conventional TFT display manufacturing processes require multiple photomasks, leading to high manufacturing costs and signal delay issues due to high impedance in large-sized panel electrode wires.
Innovation Solution
A method that reduces the number of photomasks by forming a conductive stack layer with a transparent conductive layer and a first metal layer, followed by patterning and reflowing a photoresist layer to create a conductive stack layer with reduced impedance, thereby forming a display device with improved signal transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photomask processes are used to form gate, semiconductor layer, source/drain, protection layer and transparent electrode, then the TFT structure can be formed, but the manufacturing cost increases and the number of photomasks required increases
Solution Approach 1:
The patent combines the formation of the gate electrode and the first metal layer into a single conductive stack layer formed by one photomask process. The transparent conductive layer and the first metal layer are patterned together to create the gate structure, eliminating the need for separate photomask steps that were previously required for each layer.
Solution Approach 2:
The conductive stack layer serves multiple functions: it acts as the gate electrode, provides electrical connection, and forms part of the pixel electrode structure. This multi-functional design reduces the number of separate components and manufacturing steps required.
2Reliability
If conventional photomask processes are used to form gate, semiconductor layer, source/drain, protection layer and transparent electrode, then the TFT structure can be formed, but the number of photomasks required increases
Solution Approach 1:
The patent combines the formation of the gate electrode and the first metal layer into a single conductive stack layer formed by one photomask process. The transparent conductive layer and the first metal layer are patterned together to create the gate structure, eliminating the need for separate photomask steps that were previously required for each layer.
3Area of stationary object
If large-sized panel electrode wires are used, then the display device can be made larger, but the signal delay due to impedance increases
Solution Approach 1:
The patent uses a composite conductive structure consisting of a transparent conductive layer (such as ITO) and a first metal layer (such as aluminum or its alloy) stacked together. This composite structure combines the transparency of the oxide layer with the high electrical conductivity of the metal layer, achieving low impedance while maintaining the required optical properties for display applications.
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
The method decreases manufacturing costs and reduces signal delay by lowering the impedance in conductive wires, enhancing the performance of large-sized panel electrode wires.
Implementation Method 1
the first photoresist layer is reflowed by heat, and part of the reflowed first photoresist layer covers the channel for protection
Data Source
AI summary
A substrate comprising a thin-film-transistor (TFT) region, a pixel region, a gate-line region and a data-line region is provided. A transparent conductive layer and a first metal layer are orderly formed on the substrate. A conductive stack layer is formed within each of the TFT/pixel/gate-line regions and the end of the data-line region. Next, a first insulating layer and a semiconductor layer are orderly formed, and a patterned first insulating layer and a patterned semiconductor layer are formed above the conductive stack layer within the TFT region. Then, a second metal layer and a first photoresist layer are respectively formed. Afterwards, the second and the first metal layers are patterned by using the first photoresist layer as a photomask. Finally, the first photoresist layer is reflowed by heat, and part of the reflowed first photoresist layer covers a channel formed within the TFT region.