Double-Layer Metal Electrodes for Thin Film Transistor Array Panels
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Solution Overview
Problem
The high manufacturing cost and electrical resistance of traditional organic thin film transistor (OTFT) panels, primarily due to the use of precious metals like Au and Ag, and the limitations of Indium Tin Oxide (ITO) as electrode materials, result in increased costs for thin film transistor array panels.
Innovation Solution
A thin film transistor array panel design featuring a double-layer metal structure for source and drain electrodes, formed using a first and second metal layer with overlapping blocks, combined with a semiconductor layer and a gate electrode, where the electrodes are processed using tone-mask and etching techniques to reduce material costs and electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Au or Ag is used as electrode material to match HOMO energy level and decrease contact resistance, then electrical conductivity is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent employs a composite electrode structure consisting of multiple metal layers (e.g., Al, Mo, Ti) with different properties. The first metal layer provides low resistance and cost-effectiveness, while subsequent layers provide work function matching and stability. This composite approach achieves the electrical performance of precious metals without their high cost.
Solution Approach 2:
The patent replaces expensive precious metals (Au, Ag) with inexpensive common metals (Al, Mo, Ti) that can be deposited using standard sputtering or evaporation techniques. These cheaper materials achieve sufficient electrical performance for the application without requiring the expensive materials traditionally used.
2Ease of manufacture
If ITO is used as electrode material to reduce cost, then manufacturing cost decreases, but electrical resistance increases making it unsuitable for current transport wires
Solution Approach 1:
The patent creates a multi-layer metal composite structure where different metal layers compensate for each other's deficiencies. The first layer (Al, Mo, or Ti) provides low resistance for current transport, while subsequent layers provide appropriate work function matching, achieving both low cost and low resistance simultaneously.
Solution Approach 2:
The patent applies different metal materials to different regions or layers of the electrode structure based on functional requirements. The bottom layer uses low-resistance metals for current transport, while upper layers use metals with specific work functions for contact optimization, achieving localized functional optimization.
3Reliability
If Ag is used as electrode material to achieve good conductivity, then electrical conductivity is improved, but oxidation resistance deteriorates without protective layers
Solution Approach 1:
The patent uses multi-layer metal composites where oxidation-resistant layers (Mo, Ti) are combined with highly conductive but oxidation-sensitive layers. The oxidation-resistant layers protect the conductive layers from environmental degradation while maintaining electrical performance.
Solution Approach 2:
The patent incorporates oxidation-resistant metal layers (Mo, Ti) in the electrode structure that serve as protective barriers against oxidation before the oxidation-sensitive conductive layers are exposed to environment, preventing degradation in advance.
Data Source
AI summary
A thin film transistor array panel and a manufacturing method are disclosed herein. The thin film transistor array panel includes a data line, a first block of a source electrode, a third block of a drain electrode, and an electrode layer which are formed by a first metal layer disposed on a baseplate; a second block of the source electrode, a fourth block of the drain electrode are formed by a second metal layer which is disposed on the first metal layer. The first block and the second block overlap to combine integrally. The third block and the fourth block overlap to combine integrally. The present invention can decrease the electrical resistance of each of the source electrode and the drain electrode.