Fringe Field Switching LCD Pad Protection via Metal Layer
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Solution Overview
Problem
In fringe field switching type liquid crystal displays, the transparent conductive layers are prone to damage during etching processes, leading to degraded interface properties and potential electrical insulation issues due to exposure to etchants, particularly affecting indium-tin oxide and indium-zinc oxide materials.
Innovation Solution
A protective metal layer, such as copper or its alloys, is applied over the transparent conductive pads to prevent damage from etchants during the patterning process, ensuring the interface properties between the conductive materials remain intact by maintaining a minimal contact area and using a low resistance metal material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the transparent conductive layer is exposed for connecting with metal layers in etching processes, then the connection between conductive layers is enabled, but the transparent conductive layer is damaged by etchants leading to degraded interface properties
Solution Approach 1:
A protective metal layer is formed over the transparent conductive layer before the etching process. This preliminary protective action prevents the transparent conductive layer from direct exposure to etchants, thereby maintaining interface properties while still enabling the connection process to proceed.
Solution Approach 2:
The protective metal layer acts as an intermediary between the transparent conductive layer and the etchant. It serves as a barrier that allows the etching process to occur without the etchant directly contacting and damaging the transparent conductive layer, thus preserving the interface properties.
2Productivity
If the transparent conductive layer is exposed to etchants, then the patterning process can be completed, but electrical insulation issues occur due to damage on the conductive layer
Solution Approach 1:
The protective metal layer is deposited before the etching process to prevent damage to the transparent conductive layer. This allows the patterning process to proceed efficiently without compromising the electrical insulation properties of the conductive layer.
Solution Approach 2:
The protective metal layer, which might seem like an additional step complicating the process, actually converts the potential harm of etchant exposure into a benefit by ensuring the transparent conductive layer remains intact and maintains its electrical insulation properties throughout the patterning process.
3Reliability
If a protective layer is added over the transparent conductive pad, then damage from etchants is prevented, but the device structure becomes more complex
Solution Approach 1:
The protective metal layer serves multiple functions: it protects the transparent conductive layer from etchant damage, provides additional electrical conductivity, and facilitates the connection process. This multi-functionality reduces the need for separate protective layers, thereby minimizing the increase in device complexity.
Solution Approach 2:
The protective metal layer changes the material parameter from transparent conductive material to metal, which provides both protection and maintained conductivity. This parameter change allows a single layer to fulfill multiple roles, reducing overall structural complexity.
Data Source
AI summary
The present disclosure relates to a fringe field switching type liquid crystal display. The present disclosure suggests a fringe field switching type liquid crystal display comprising: a substrate; a gate pad disposed on the substrate; a gate insulating layer covering the gate pad; a data pad disposed on the gate insulating layer; a first passivation layer covering the data pad; a common pad disposed on the first passivation layer; a protective metal layer disposed on the common pad; a second passivation layer covering the common pad; a gate contact hole exposing the gate pad; a data contact hole exposing the data pad; and a common contact hole exposing the protective metal layer.