Organic TFT Bank Structure for Precision Patterning
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Solution Overview
Problem
The patterning of organic semiconductor materials used in thin film transistors (TFTs) is challenging due to poor chemical and optical stability, leading to difficulties in achieving good pattern precision and high possibilities of particle cross-talk between adjacent TFTs.
Innovation Solution
A method involving the formation of a bank with specific concave portions in an organic insulating film using a half-tone mask, followed by the ink-jet deposition and curing of source and drain electrodes, and an active layer, which simplifies the patterning process and enhances precision by using materials like polyethylene dioxythiophene and metal or carbon nano composites with appropriate work functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If organic semiconductor material is used as active layer, then low-temperature process and flexibility are secured, but pattern precision deteriorates and particle cross-talk occurs
Solution Approach 1:
An organic insulating film is introduced as an intermediary layer between the substrate and the organic semiconductor active layer. This film serves as a foundation for forming a bank structure that confines the active layer material, preventing particle generation and cross-talk while enabling low-temperature processing. The insulating film acts as a mediator that solves the pattern precision problem without compromising the low-temperature advantage of organic materials.
Solution Approach 2:
The organic insulating film is segmented to form a bank structure with specific concave portions. This segmentation creates distinct regions: a first concave portion for the source electrode, a second concave portion for the drain electrode, and a third concave portion for the active layer. This segmented structure confines the organic semiconductor material precisely, improving pattern precision while maintaining compatibility with low-temperature processing.
2Ease of manufacture
If conventional patterning method is used, then simple process is maintained, but pattern precision deteriorates and cross-talk increases
Solution Approach 1:
The bank structure is formed in advance within the organic insulating film before depositing the organic semiconductor active layer. This preliminary action creates pre-defined concave portions that guide and confine the active layer material during subsequent deposition. By preparing the confinement structure beforehand, the method achieves high pattern precision without requiring complex in-situ patterning techniques, thus maintaining ease of manufacture.
Solution Approach 2:
The organic insulating film serves as an intermediary that enables simple patterning. By forming the bank structure within this film, the method provides a straightforward approach to achieve precise patterns. The insulating film acts as a sacrificial or structural intermediary that simplifies the overall patterning process while ensuring high precision, avoiding the need for multiple complex lithography and etching steps.
3Loss of substance
If organic semiconductor material is patterned directly, then material usage is efficient, but chemical and optical stability deteriorates leading to poor pattern quality
Solution Approach 1:
The organic insulating film is segmented into a bank structure with distinct concave portions before introducing the organic semiconductor material. This segmentation approach allows the active layer material to be deposited only in the designated third concave portion, confined by the bank structure. This method maintains material usage efficiency while the bank structure protects the organic semiconductor from degradation, improving chemical and optical stability and preventing particle generation.
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 patterning process, improves pattern precision, and reduces the likelihood of cross-talk between TFTs, enabling the manufacture of high-quality thin film transistors suitable for flexible organic light emitting displays.
Implementation Method 1
The bank is formed by exposing the organic insulating film using a half tone mask and developing the exposed organic insulating film
Implementation Method 2
The source electrode and the drain electrode are formed by dropping source and drain electrode material in the first and second concave portions using an ink-jet method and curing the substrate
Implementation Method 3
forming an active layer in the third concave portion, the active layer contacting the source electrode and the drain electrode
Data Source
AI summary
A method of manufacturing a thin film transistor is capable of enhancing pattern precision of an organic semiconductor layer and simplifying a patterning process. The method includes forming an organic insulating film on a substrate and forming a bank having the first and second concave portions and a third concave portion in the organic insulating film, the third concave portion being formed on the first and second concave portions. The method further includes forming a source electrode and a drain electrode in the first and second concave portions and forming an active layer in the third concave portion, the active layer contacting the source electrode and the drain electrode.