Conductive Pattern Structure With Sidewall Metal Protection
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Solution Overview
Problem
In thin film transistor liquid crystal displays (TFT-LCDs), the increasing size and resolution lead to signal delay in gate electrode lines, causing uneven display brightness and reduced contrast due to the oxidation and ion diffusion of low resistance metals used for electrodes, which deteriorates the performance of thin film transistors.
Innovation Solution
A conductive pattern structure comprising a first metal pattern with a second metal pattern covering its side surfaces, where the second metal pattern is more active than the first, formed using materials like nickel, molybdenum, or titanium to prevent oxidation and ion diffusion, and a buffer layer to further protect the first metal pattern, which can be copper-based or silver-based.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low resistance metal (Cu, Ag) is used for manufacturing gate lines and electrodes, then electrical conductivity is improved, but oxidation and ion diffusion occur causing performance deterioration
Solution Approach 1:
A buffer layer made of Mo, Nb, Ti, or their alloys is introduced between the low resistance metal (Cu or Ag) and the semiconductor layer. This intermediary buffer layer prevents direct contact, thereby blocking oxidation of the low resistance metal and preventing metal ion diffusion into the semiconductor layer, while maintaining electrical conductivity through the structure.
Solution Approach 2:
The conductive structure is designed as a composite material system combining low resistance metal (Cu or Ag) with buffer layer materials (Mo, Nb, Ti or their alloys). This composite structure leverages the low resistivity of Cu/Ag for electrical conduction while the buffer layer provides oxidation resistance and ion diffusion barrier properties.
2Manufacturing precision
If gate line length increases to reduce pixel size and improve resolution, then display quality is improved, but signal delay increases causing uneven brightness
Solution Approach 1:
The resistivity parameter of the gate line material is changed from high resistivity metals (Ta, Cr, Mo) to low resistivity metals (Cu, Ag). This parameter change reduces electrical resistance in long gate lines, minimizing signal delay and voltage drop, thereby preventing uneven brightness even when gate line length increases for higher resolution displays.
3Reliability
If buffer layer is added to prevent oxidation and ion diffusion, then reliability is improved, but device complexity increases
Solution Approach 1:
Instead of protecting all metal structures uniformly, the buffer layer is selectively applied only where needed - specifically between the low resistance metal and the semiconductor layer where ion diffusion is most harmful. This localized approach provides necessary protection while minimizing added structural complexity.
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 solution effectively prevents the oxidation of the first metal pattern, maintains electrical conductivity, reduces production complexity and costs, and enhances the yield of TFT-LCDs by using a simpler electrolysis cell reaction method for manufacturing, thereby improving display quality.
Implementation Method 1
the low resistance metal is easy to be oxidized
Implementation Method 2
a simpler electrolysis cell reaction method for manufacturing
Implementation Method 3
metal ions of the low resistance metal are easy to diffuse into a semiconductor layer
Data Source
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AI summary
A conductive pattern structure is provided by the embodiment of present disclosure. The conductive pattern structure (20) includes: a first metal pattern (201) and a second metal pattern (202). The second metal pattern (202) covers at least a portion of a side surface of the first metal pattern (201); and an activity of a metal material of the first metal pattern (201) is weaker than an activity of a metal material of the second metal pattern (202). The embodiment of present disclosure prevents the side surface of the first metal pattern (201) from being oxidized by forming the second metal pattern (202) covering at least a portion of the side surface of the first metal pattern (201), in this way, the problem that the electrical conductivity of the first metal pattern (201) reducing is avoided, and the problem that the product yield declining is avoided. In addition, the present disclosure further reduces the requirements for the production equipment and the external environment, in this way, the complexity of the manufacturing process of the conductive pattern structure is reduced and the production cost is reduced.