Inlay Gate Line Structure for Copper LCD Interconnects
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Solution Overview
Problem
The miniaturization of metal interconnections in LCD devices leads to increased RC delay due to high resistance and capacitance, and the use of copper materials results in issues like oxidation, corrosion, and inter-diffusion, complicating the manufacturing process and reducing signal transmission efficiency.
Innovation Solution
A manufacturing method for a thin-film transistor matrix substrate that incorporates an inlay type gate line structure with a first and second barrier layer, a semi-conductive layer, and a transparent electrode layer, using copper as the metal line to reduce resistance and prevent copper ion diffusion, while maintaining low contact resistance and improving adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If copper material is used as metal line to reduce resistance, then signal transmission rate is improved, but oxidation, moisture corrosion, and inter-diffusion problems occur
Solution Approach 1:
A barrier layer comprising a first barrier layer and a second barrier layer is introduced as an intermediary between the copper metal line and surrounding materials. The first barrier layer prevents copper ion diffusion, while the second barrier layer prevents oxidation and moisture corrosion, allowing copper to maintain its low resistance properties without suffering from its inherent stability issues.
Solution Approach 2:
The solution employs a composite structure combining copper metal lines with multiple barrier layers (first barrier layer and second barrier layer). This composite material system leverages the low resistance of copper while the barrier layers provide protective functions, creating a composite structure that achieves both electrical performance and environmental stability.
2Ease of manufacture
If conventional Al/Ti or Ti/Al/Ti metal line structure is used, then manufacturing process is simple, but sheet resistance is high
Solution Approach 1:
The invention changes the material parameter from conventional aluminum-based metals to copper, which has inherently lower resistance. Despite the increased complexity of handling copper, the barrier layer structure simplifies the manufacturing process by preventing copper oxidation and ion diffusion, thereby achieving both low sheet resistance and ease of manufacture.
3Reliability
If repair line is added to overcome broken line defect, then circuit continuity is restored, but signal pathway length increases causing RC delay
Solution Approach 1:
The barrier layer structure is established in advance during the manufacturing process, creating a reliable copper metal line that is resistant to oxidation and ion diffusion. This preliminary protective action prevents broken line defects from occurring in the first place, eliminating the need for repair lines and avoiding the associated RC delay penalty.
4Ease of manufacture
If gate profile angle is 90° instead of 60°-80°, then manufacturing is easier, but step coverage is poor causing cracks and S-G leakage
Solution Approach 1:
The barrier layer structure provides localized protection at critical interfaces. The first barrier layer is positioned where copper ion diffusion is most likely to occur, while the second barrier layer protects against oxidation and moisture at the exposed surfaces. This local quality approach ensures that the 90° gate profile does not compromise the protective function of the barrier layers.
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 method enhances signal transmission rates by reducing RC delay, improves yield by minimizing defects, and avoids the need for longer repair lines, thus reducing manufacturing costs and increasing efficiency.
Implementation Method 1
a first barrier layer which is sandwiched in between the copper layer and the transparent layer to avoid copper ions diffusing into the transparent layer
Implementation Method 2
utilization of copper can improve the above difficulties in the design of the conventional panel
Implementation Method 3
after dry etching Gate 100 profile in TFT structure formed by the conventional process
Implementation Method 4
When the insulated layer 200 is sputtered on the gate
Data Source
AI summary
A lower substrate for a liquid crystal display device and the method of making the same are disclosed. The method includes steps of: (a) providing a substrate; (b) forming a patterned transparent layer having plural recess on the substrate; (c) forming a first barrier layer on the surface of the recess; (d) coating a first metal layer on the first barrier layer and making the surfaces of the first metal layer and the transparent layer in substantially the same plane; and (e) forming a first insulated layer and a semi-conductive layer in sequence. The method further can optionally comprise the steps of: (f) forming a patterned second metal layer, wherein part of the semi-conductive layer is exposed, thus forming the source electrode and the drain electrode; and (g) forming a transparent electrode layer on part of the transparent layer and part of the second metal layer.