TFT Barrier Patterns Using Copper Nitride and Pure Copper
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Solution Overview
Problem
The existing methods for fabricating thin film transistors (TFTs) in LCD devices face complications due to the use of different materials for source and drain electrodes, leading to issues like galvanic corrosion and low adhesive strength, particularly when using MoTi alloy targets, which result in complex fabrication processes and impurity diffusion.
Innovation Solution
The method involves forming gate and data lines on a substrate, followed by the deposition of copper nitride and pure copper barrier patterns, which simplifies the process by using the same etchant and prevents material diffusion, thereby improving adhesive strength and reducing fabrication complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different materials are used for source and drain electrodes, then device performance is improved, but fabrication complexity increases and galvanic corrosion occurs
Solution Approach 1:
The patent combines the source and drain electrode materials into a single material system (copper-based alloy) rather than using different materials for each electrode. This merging approach eliminates the need for separate material deposition processes and prevents galvanic corrosion between dissimilar metals, thereby reducing fabrication complexity while maintaining device performance through optimized alloy composition
Solution Approach 2:
The patent changes the material parameter from using different materials for source and drain electrodes to using a uniform copper-based alloy for both. This parameter change simplifies the fabrication process by eliminating the need for multiple material deposition steps and prevents galvanic corrosion, while device performance is maintained through controlled alloy composition and heat treatment parameters
2Strength
If MoTi alloy target is used, then adhesive strength is improved, but impurity diffusion increases and fabrication complexity increases
Solution Approach 1:
The patent extracts the problematic MoTi alloy material and replaces it with a copper-based alloy system. This extraction eliminates the impurity diffusion issues associated with MoTi while maintaining adhesive strength through the copper-based material system, thereby reducing fabrication complexity and improving material purity
Solution Approach 2:
The patent adopts a copper-based alloy material that is more readily available and easier to process than MoTi alloy. This material substitution reduces fabrication complexity and eliminates impurity diffusion problems, while the necessary adhesive strength is achieved through optimized copper alloy composition and subsequent heat treatment processes
3Reliability
If multiple deposition processes are used, then material properties are optimized, but fabrication complexity increases
Solution Approach 1:
The patent merges multiple deposition processes into a single deposition step by using a uniform copper-based alloy material for both source and drain electrodes. This consolidation reduces fabrication complexity while maintaining optimized material properties through controlled alloy composition and subsequent unified heat treatment processes
Solution Approach 2:
The patent employs a universal copper-based alloy material that serves both as source and drain electrode material, eliminating the need for separate material deposition processes. This universal material approach simplifies fabrication while maintaining optimized electrical and mechanical properties through controlled alloy composition and heat treatment
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 fabrication process, prevents galvanic corrosion, and enhances the adhesive strength of the barrier patterns, leading to improved performance and reliability of the TFTs in LCD devices.
Implementation Method 1
the deposition of copper nitride and pure copper barrier patterns
Data Source
AI summary
According to an embodiment, a method of fabricating a thin film transistor comprises forming a gate electrode on a substrate; forming a gate insulating layer on the gate electrode; forming a semiconductor layer on the gate insulating layer, the semiconductor layer corresponding to the gate electrode; forming first and second barrier patterns on the semiconductor layer, the first and second barrier patterns including copper nitride; and forming source and drain electrodes on the first and second barrier patterns, respectively, the source and drain electrodes including pure copper.