Thin Film Transistor Array Substrate Using Three-Round Mask Process
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Solution Overview
Problem
The manufacturing process of thin film transistor array substrates for liquid crystal display panels is complex and costly due to the need for multiple mask processes, limiting further reduction in manufacturing costs and complexity.
Innovation Solution
A thin film transistor array substrate and manufacturing method that reduces the number of mask processes by using a three-round mask process, incorporating specific passivation layers with varying etch rates and materials like silicon nitride, silicon oxide, and organic insulating materials, and employing a lift-off process to simplify the pixel electrode formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a four-round mask process is used to reduce manufacturing steps, then the number of mask processes is reduced compared to the five-round process, but the manufacturing process remains complex and manufacturing costs are not sufficiently reduced
Solution Approach 1:
The patent merges multiple functions into the three-round mask process by using a first passivation layer that serves both as a protective layer and as a layer to be patterned along with the pixel electrode. The lift-off process combines deposition and patterning steps, eliminating the need for separate mask processes for each layer while maintaining manufacturing precision.
Solution Approach 2:
The patent applies preliminary action by forming the first passivation layer before the pixel electrode pattern, and using the lift-off method where the photoresist pattern is formed in advance to define the pixel electrode shape. This preliminary structuring allows subsequent layers to be deposited and automatically patterned, reducing the need for additional mask processes.
2Manufacturing precision
If multiple mask processes are used to ensure manufacturing precision, then the manufacturing precision is maintained, but the manufacturing cost and process complexity increase
Solution Approach 1:
The lift-off process employs self-service by using the photoresist pattern itself as the masking layer for metal deposition. The deposited material automatically forms the desired pattern and lifts off where the photoresist is present, eliminating the need for separate photolithography and etching steps while maintaining precise pattern definition.
Solution Approach 2:
The patent utilizes parameter changes in the passivation layer materials (silicon nitride, silicon oxide, organic insulating materials) with varying etch rates to achieve selective removal during the lift-off process. By controlling deposition and etching parameters, precise patterning is achieved without requiring multiple mask processes.
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 simplifies the manufacturing process, reduces defects, and decreases manufacturing costs by effectively using a three-round mask process with the lift-off method, enhancing manufacturing yield and reducing the complexity of the substrate configuration.
Implementation Method 1
incorporating specific passivation layers with varying etch rates and materials like silicon nitride, silicon oxide, and organic insulating materials, and employing a lift-off process
Data Source
AI summary
A method of manufacturing a thin film transistor array substrate includes forming a gate pattern on a substrate, forming a gate insulating film on the substrate, forming a source/drain pattern and a semiconductor pattern on the substrate, forming first, second, and third passivation films successively on the substrate. Over the above multi-layered passivation film forming a first photoresist pattern including a first portion formed on part of the drain electrode and on the pixel region, and a second portion. The second portion is thicker than the first portion. Then, patterning the third passivation film using the first photoresist pattern, forming a second photoresist pattern by removing the first portion of the first photoresist pattern, forming a transparent electrode film on the substrate, removing the second photoresist pattern and the transparent electrode film disposed on the second photoresist pattern, and forming a transparent electrode pattern on the second passivation layer.