Thin-Film Transistor Gate Etching to Block Leakage Paths
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Solution Overview
Problem
The electrical characteristics of thin film transistors in display apparatuses deteriorate due to leakage currents, affecting display quality, particularly in devices like plasma, liquid crystal, and organic light emitting displays, which require improved manufacturing methods to enhance transistor performance.
Innovation Solution
A method of manufacturing thin film transistors involves forming an active pattern on a substrate, followed by sequential layers of insulating and gate electrodes, with specific etching processes to create a leakage current-free region by removing conductive by-products, including indium, using photoresist patterns and etching solutions, and forming source and drain regions to prevent current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing methods are used to form gate electrodes, then the manufacturing process is simple, but leakage current paths are formed due to conductive by-products, deteriorating electrical characteristics
Solution Approach 1:
The gate electrode formation process is segmented into multiple stages: forming a preliminary gate electrode, forming an insulating pattern, and then forming the final gate electrode. This segmentation allows removal of conductive by-products between stages, preventing leakage current paths while maintaining overall process control
Solution Approach 2:
A preliminary gate electrode is formed first before the final gate electrode. This preliminary structure serves as a placeholder that allows subsequent formation of the insulating pattern and removal of conductive by-products, preventing leakage issues in the final device
2Ease of manufacture
If wet etching is used to form the gate electrode, then the process is simple and cost-effective, but conductive by-products remain on the insulating pattern, creating leakage current paths
Solution Approach 1:
Conductive by-products are selectively removed by etching the insulating layer to expose and eliminate these by-products from the insulating pattern surface, while preserving the gate electrode structure
Solution Approach 2:
The insulating pattern serves as an intermediary structure that both protects underlying layers during etching and provides a surface where conductive by-products can be selectively removed through controlled etching 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 method effectively blocks leakage current paths, thereby improving the electrical characteristics and durability of thin film transistors, enhancing the performance and longevity of display apparatuses.
Implementation Method 1
forming a photoresist pattern on the gate electrode layer
Implementation Method 2
forming a preliminary gate electrode by wet etching the gate electrode layer
Implementation Method 3
forming an insulating pattern by dry etching the insulating layer
Implementation Method 4
removing conductive by-products, including indium, using photoresist patterns and etching solutions
Data Source
AI summary
A method of manufacturing a thin film transistor includes: forming an active pattern on a substrate; forming an insulating layer and a gate electrode layer on the active pattern in order; forming a photoresist pattern on the gate electrode layer; forming a preliminary gate electrode by wet etching the gate electrode layer using the photoresist pattern; forming an insulating pattern by dry etching the insulating layer using the photoresist pattern and the preliminary gate electrode; and forming a gate electrode by wet etching a side surface of the preliminary gate electrode using the photoresist pattern.