TFT Contact Resistance Reduction via Dual Metal Layer Interconnect
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high resistance and impedance of ITO layers in traditional TFT liquid crystal displays lead to increased contact impedance between metal layers, resulting in poor display effects and reduced product yield rates.
Innovation Solution
A manufacturing method that involves depositing a conductive film through a contact hole etched in both silicon nitride protective films to connect metal layers, reducing the connecting distance and impedance between them, using ITO, AZO, or IZO as conductive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a conventional glass substrate is used, then the substrate has high strength and good flatness, but the substrate is heavy and expensive
Solution Approach 1:
The patent changes the material parameter from conventional glass to flexible polymer materials (such as polyethylene terephthalate or polypropylene), fundamentally altering the substrate's physical properties to achieve both lightweight and flexible characteristics while maintaining sufficient mechanical strength through material selection and structural design
Solution Approach 2:
The patent employs composite structures by combining flexible polymer substrates with various functional layers (such as buffer layers, emission layers, and protective coatings) to create a composite material system that achieves the desired balance between flexibility, strength, and lightweight properties
2Adaptability or versatility
If a flexible polymer substrate is used, then the substrate is lightweight and flexible, but the substrate has poor flatness and is difficult to control
Solution Approach 1:
The patent applies preliminary flattening treatments to the flexible substrate before the main manufacturing process, including pre-stretching, pre-flattening, and pre-alignment operations, to establish a stable baseline flatness that facilitates subsequent precise manufacturing operations
Solution Approach 2:
The patent controls the physical parameters of the flexible substrate during manufacturing, including temperature, humidity, and tension, to dynamically adjust and maintain optimal flatness conditions throughout the manufacturing process, transforming the substrate's physical state to achieve desired flatness
3Adaptability or versatility
If the substrate is made flexible, then the display device can be bent, but the alignment of liquid crystal molecules becomes difficult to control
Solution Approach 1:
The patent applies different surface treatments to different regions of the flexible substrate, with specific alignment layers and surface modifications applied only in the liquid crystal deposition areas, allowing the flexible substrate to maintain its overall flexibility while providing localized high-precision alignment control where needed
Solution Approach 2:
The patent pre-treats the flexible substrate surface with alignment layers and surface modifications before liquid crystal deposition, establishing predetermined alignment patterns and forces that guide liquid crystal molecule orientation even on flexible, bent substrates
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 effectively lowers contact impedance, enhances display quality, and increases product yield and competitive capability by minimizing the resistance and impedance between metal layers.
Implementation Method 1
depositing a conductive film on the second metal layer where the second silicon nitride protective film is etched, and on a contact hole which passes through the second silicon nitride protective film and the first silicon nitride protective film, so as to connect and conduct with the first metal layer and the second metal layer
Implementation Method 2
depositing a first silicon nitride protective film on a first metal layer formed on a substrate; depositing a second metal layer and a second silicon nitride protective film on the first silicon nitride protective film in order
Data Source
Figure 1~2
Figure 3
AI summary
Provided are a TFT liquid crystal display device and a method for manufacturing the same. The TFT liquid crystal display device comprises: a substrate (21); a first metal layer (22) provided on the substrate (21), a first silicon nitride protective film (23) being deposited on the first metal layer (22); a second metal layer (24) deposited on the first silicon nitride protective film (23), a second silicon nitride protective film (25) being deposited on the second metal layer (24); and a conductive film (28) deposited on the second metal layer (24) where the second silicon nitride protective film (25) is etched away, and connected to the first metal layer (22) through a contact hole (26) which passes through the second silicon nitride protective film (25) and the first silicon nitride protective film (23), so that the first metal layer (22) is connected to the second metal layer (24). Since a connection distance of the conductive thin film (28) between different metal layers is reduced, a contact resistance between the metals is reduced, thereby effectively reducing the contact resistance and improving the product yield.