Liquid Crystal Display Thin Film Transistor Substrate Fabrication
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Solution Overview
Problem
The manufacturing process of liquid crystal display devices with horizontal electric field applying type is complex and costly due to the requirement of multiple mask processes, particularly in forming the thin film transistor substrate.
Innovation Solution
A simplified manufacturing process for the liquid crystal display device involves forming a thin film transistor substrate with a multiple-layer conductive structure using a transparent and opaque conductive layer, employing a reduced number of mask processes through the use of half tone or diffractive exposure masks, and integrating a storage capacitor with overlapping electrodes to enhance capacitance and signal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple mask processes are used to form the thin film transistor substrate, then the device characteristics and light transmittance are improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent combines multiple mask processes into a single mask process by integrating the formation of the thin film transistor substrate and color filter substrate into one manufacturing flow. The first mask pattern is formed to define both the thin film transistor structures and color filter structures simultaneously, reducing the total number of mask processes from multiple separate processes to just one process, thereby simplifying manufacturing while maintaining device characteristics
Solution Approach 2:
The first mask pattern serves multiple functions: it defines the gate lines, source/drain electrodes for the thin film transistor, and simultaneously defines the color filter structures. This multi-functional mask pattern eliminates the need for separate mask processes for each component, reducing manufacturing complexity while maintaining precision in device formation
2Illumination intensity
If multiple mask processes are used to form the thin film transistor substrate, then the light transmittance and contrast ratio are improved, but the manufacturing cost and time increase
Solution Approach 1:
The patent merges the formation of thin film transistor structures and color filter structures into a single mask process, reducing the total number of manufacturing steps. This consolidation maintains the optical performance (light transmittance and contrast ratio) while significantly improving manufacturing efficiency by eliminating repeated mask alignment and processing cycles
Solution Approach 2:
The first mask pattern is formed in advance to define all subsequent structures including thin film transistor electrodes and color filters. This preliminary action establishes the complete pattern layout before any deposition or etching processes, allowing subsequent layers to be formed without requiring additional mask alignments, thus improving productivity while maintaining optical quality
3Reliability
If a protective film is used during manufacturing, then the channel reliability is improved, but the manufacturing complexity and additional processes are required
Solution Approach 1:
The patent removes the protective film step from the manufacturing process by forming the second mask pattern directly on the exposed active layer without requiring protective film coverage. The active layer is exposed through the first mask pattern, and the second mask pattern is formed directly on this exposed area, eliminating the need for protective film deposition, removal, and associated alignment processes while maintaining channel reliability through proper pattern definition
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 reduces the complexity and cost of the manufacturing process, improves the reliability of the device characteristics, and enhances the productivity of the liquid crystal display device by minimizing the number of mask processes and eliminating the need for a protective film, while maintaining stable channel reliability and improved light transmittance and contrast ratio.
Implementation Method 1
The liquid crystal 24 having a dielectric anisotropy is rotated in accordance with an electric field formed by a data signal from a pixel electrode 22 and a common voltage Vcom from the common electrode 8 to control light transmittance
Implementation Method 2
The gate line, the gate electrode, the pixel electrode, the common electrode, the common line, and the pad include a transparent conductive layer... The gate line, the gate electrode, the common line have a multiple-layer structure including the transparent conductive layer and a substantially opaque conductive layer
Data Source
AI summary
A liquid crystal display device and a fabricating method thereof for simplifying a process are disclosed. In the method of fabricating the liquid crystal display device, a first conductive pattern group including a gate line and a gate electrode, a common line and a common electrode, a pixel electrode and a pad is formed on a substrate. An insulating film including a plurality of contact holes and a semiconductor pattern is formed on the first mask pattern group. And a second conductive pattern group including a data line, a source electrode and a drain electrode is formed on an insulating film provided with the semiconductor pattern, and exposes an active layer of the semiconductor pattern.