Alignment Mark for Polysilicon Crystallization in OLED Displays
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Solution Overview
Problem
The existing technologies for organic light emitting displays lack precision in controlling the position of crystallization of amorphous silicon and forming active layers, leading to non-uniform properties of thin film transistors and luminance in organic light emitting diodes.
Innovation Solution
The method involves forming an alignment mark on a substrate's non-display region, using a catalytic metal to control the crystallization of amorphous silicon into polysilicon, and forming an active layer with optimal grain boundaries and position, which improves the uniformity of thin film transistors and organic light emitting diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional amorphous silicon crystallization and active layer formation methods are used, then the manufacturing process can be completed, but the position control of crystallization and active layer formation is imprecise, leading to non-uniform thin film transistor properties and luminance
Solution Approach 1:
The patent applies preliminary action by forming alignment marks on the substrate before the crystallization and active layer formation processes. These alignment marks serve as pre-established reference points that guide the subsequent manufacturing steps, ensuring precise position control of the polysilicon crystallization region and active layer formation. This preliminary positioning structure enables accurate alignment without requiring complex real-time control during the actual deposition and crystallization processes.
2Manufacturing precision
If alignment marks are formed on the substrate to precisely control crystallization position, then manufacturing precision is improved, but the device complexity increases due to additional fabrication steps
Solution Approach 1:
The patent applies segmentation by dividing the substrate into distinct functional regions: alignment mark regions and active device regions. The alignment marks are formed as separate, discrete structures on the substrate that serve solely as positioning references. This segmentation allows the alignment function to be independently optimized without interfering with the active device fabrication, and the additional complexity is localized to specific areas rather than affecting the entire device structure.
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 results in improved uniformity of thin film transistor characteristics, such as S-factor and off current, and achieves uniform luminance even in larger panel sizes.
Implementation Method 1
using a catalytic metal to control the crystallization of amorphous silicon into polysilicon
Data Source
AI summary
An organic light emitting display and a fabricating method thereof in which an alignment mark is formed in the non-display region. The organic light emitting display includes a substrate having a display region and a non-display region; a buffer layer formed the overall substrate; a gate insulating layer; a gate electrode formed on the gate insulating layer corresponding to the active layer; an interlayer dielectric layer formed on the gate insulating layer; a source/drain electrode formed on the interlayer dielectric layer and electrically coupled to the active layer; an insulating layer formed on the source/drain electrode; and an organic light emitting diode formed on the insulating layer and electrically coupled to the source/drain electrode. Further, the organic light emitting display includes an alignment mark formed on one of the substrate and the buffer layer.