OLED Electrode Aluminum Layering to Prevent Grain-Induced Defects
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Solution Overview
Problem
The manufacturing process of OLED display devices faces challenges in maintaining reliability, particularly due to issues related to the formation of crystal grains during the deposition of aluminum layers, which can affect the flatness and integrity of the electrode structures.
Innovation Solution
A manufacturing method is employed where aluminum layers are formed in a controlled manner, with cooling after each layer to prevent excessive grain growth, followed by etching to create a partition structure that includes a lower and upper portion, ensuring precise formation of electrodes and organic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick aluminum layer is formed to ensure sufficient coverage and conductivity, then the electrical performance is improved, but the aluminum crystal grains grow larger during sputtering, causing surface non-flatness and manufacturing defects
Solution Approach 1:
The aluminum layer is divided into multiple thin layers (first aluminum layer 611 and second aluminum layer 612, each 200-500 nm thick) instead of forming one thick layer. This segmentation prevents crystal grain growth while achieving the required total thickness and electrical performance, with each thin layer maintaining surface flatness during sputtering
Solution Approach 2:
The first aluminum layer 611 is formed and cooled to room temperature before forming the second aluminum layer 612. This preliminary cooling action prevents crystal grain growth in the first layer, establishing a flat surface foundation that prevents grain growth in subsequent layers
2Manufacturing precision
If the aluminum layer is cooled to prevent crystal grain growth, then surface flatness is maintained, but the manufacturing process time increases due to additional cooling steps
Solution Approach 1:
Cooling the first aluminum layer 611 to room temperature is performed as a preliminary action before depositing the second aluminum layer 612. This timing of the cooling action integrates smoothly into the manufacturing sequence, preventing crystal grain growth while maintaining efficient process flow
Solution Approach 2:
The temperature parameter of the aluminum layer is changed from elevated (during sputtering) to room temperature (after sputtering). This parameter change prevents crystal grain growth while the process is designed to minimize time loss through efficient temperature management and continuous manufacturing
3Reliability
If multiple aluminum layers are formed to control crystal grain growth, then manufacturing reliability is improved, but the device structure and manufacturing complexity increase
Solution Approach 1:
The aluminum structure is segmented into two thin layers (611 and 612) with controlled thicknesses of 200-500 nm each, separated by a thin film 620. This segmentation achieves manufacturing reliability by preventing crystal grain growth while maintaining a manageable and well-defined layered structure
Solution Approach 2:
The partition structure is formed as a composite of multiple materials including the first aluminum layer 611, second aluminum layer 612, and thin film 620. This composite structure combines the benefits of each material layer to achieve both crystal grain control and structural integrity
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 enhances the reliability of OLED display devices by maintaining the structural integrity of electrodes and organic layers, preventing defects caused by crystal grain formation, thus improving the overall performance and longevity of the display.
Implementation Method 1
cooling the first aluminum layer
Implementation Method 2
issues related to the growth of aluminum crystal grains during sputtering
Data Source
AI summary
A manufacturing method of a display device includes forming a lower electrode, forming an insulating layer overlapping the lower electrode, forming a first aluminum layer above the insulating layer, cooling the first aluminum layer, forming a second aluminum layer on the first aluminum layer, forming a thin film above the second aluminum layer, forming a partition including a lower portion and an upper portion, forming an organic layer located on the lower electrode, and forming an upper electrode which is located on the organic layer and is in contact with the lower portion of the partition.