OLED Display TFT Layout to Protect Oxide Semiconductors
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in maintaining the quality and reliability of oxide semiconductor patterns due to exposure to hydrogen particles during etching and heat treatment processes, leading to poor electrical characteristics and leakage currents, which affect the representation of grayscale images.
Innovation Solution
The device incorporates a structure with a polycrystalline semiconductor pattern and an oxide semiconductor pattern in different layers, using a connection electrode to connect the polycrystalline semiconductor pattern and source/drain electrodes before forming the oxide semiconductor pattern, thereby reducing leakage current and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If oxide semiconductor patterns are formed in the same layer as polycrystalline semiconductor patterns and exposed to etching conditions, then manufacturing process is simplified, but quality and reliability of oxide semiconductor materials deteriorate during heat treatment process
Solution Approach 1:
The patent divides the semiconductor patterns into different layers: polycrystalline semiconductor patterns in a first layer and oxide semiconductor patterns in a second layer. This segmentation allows each material type to be optimized for its specific requirements, preventing degradation of oxide semiconductors during heat treatment while maintaining manufacturing efficiency.
Solution Approach 2:
The patent transitions from a planar arrangement where all semiconductor patterns are in the same layer to a vertical stacking arrangement with polycrystalline and oxide semiconductor patterns in different layers. This dimensional change enables differential treatment of each material type during processing, particularly protecting oxide semiconductors from harmful heat treatment effects.
2Reliability
If different semiconductor materials are used in different layers, then electrical characteristics can be optimized, but leakage current increases due to hydrogen particle exposure during etching and heat treatment
Solution Approach 1:
The patent introduces an intermediary protective layer between the etching/heat treatment process and the oxide semiconductor pattern. This protective layer prevents hydrogen particles generated during etching and heat treatment from penetrating into and degrading the oxide semiconductor material, thereby reducing leakage current while maintaining optimized electrical characteristics.
Solution Approach 2:
The patent applies preliminary protective measures by positioning the oxide semiconductor pattern in a separate layer that is shielded from hydrogen particle exposure during etching and heat treatment processes. This preemptive structural arrangement prevents the harmful effects of hydrogen exposure before they can occur, reducing leakage current.
3Ease of manufacture
If oxide semiconductor patterns are exposed to heat treatment process, then manufacturing process is simplified, but degradation of oxide semiconductor materials occurs leading to poor electrical characteristics
Solution Approach 1:
The patent segments the semiconductor structures into different layers, placing oxide semiconductor patterns in a protected second layer away from the direct path of heat treatment processes. This allows heat treatment to be applied to polycrystalline semiconductor patterns in the first layer without degrading the oxide semiconductor materials, maintaining both manufacturing simplicity and electrical characteristics quality.
Data Source
AI summary
An organic light emitting display device including both a polycrystalline semiconductor element and an oxide semiconductor element, and a method of manufacturing the display device are disclosed. In order to solve the damage of an oxide semiconductor pattern during a heat treatment process in the process of forming the oxide semiconductor element, until the process of forming the polycrystalline semiconductor element is completed, after one portion of a connection electrode connecting a polycrystalline semiconductor pattern to source and drain electrodes is formed in advance, then by forming the other portion of the connection electrode for completing the connection between the source and drain electrodes to the polycrystalline semiconductor pattern in the process of forming the oxide semiconductor element, the connection electrode can have a connection node between two edges thereof, and thereby, the performance of the oxide semiconductor element can be improved.