Display Device Protective Elements for Oxide TFT ESD and Moisture
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Solution Overview
Problem
Oxide-semiconductor thin-film transistors in high-definition display devices are prone to deterioration due to electrostatic discharge and moisture ingress during manufacturing processes.
Innovation Solution
A display device structure with a stacked configuration of inorganic and organic insulating films and conductive layers, including protective elements along display wires, to prevent electrostatic discharge and moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide semiconductor TFTs are used in high-definition display devices, then leakage current is reduced and display quality is improved, but the transistors become vulnerable to electrostatic discharge and moisture ingress during manufacturing
Solution Approach 1:
The patent applies preliminary action by forming protective inorganic insulating films (silicon nitride, silicon oxide) and organic insulating films before the oxide semiconductor layer is exposed or damaged. These films are deposited in advance to create a protective barrier that prevents electrostatic discharge and moisture ingress during subsequent manufacturing steps, addressing the vulnerability of oxide semiconductor TFTs before the harmful effects can occur.
Solution Approach 2:
The patent implements beforehand cushioning by introducing multiple layers of protective insulating films (including silicon nitride, silicon oxide, and organic resin materials) that act as cushions against electrostatic discharge and moisture. These films are strategically positioned to absorb or deflect harmful factors before they can reach the sensitive oxide semiconductor layer, providing a buffer protection mechanism.
2Object-affected harmful factors
If multiple inorganic and organic insulating films are stacked to protect against electrostatic discharge and moisture, then protection effectiveness is improved, but device structure complexity increases
Solution Approach 1:
The patent applies composite materials by combining different types of insulating films (inorganic: silicon nitride, silicon oxide; organic: resin materials) in a stacked configuration. Each material provides complementary protection properties - inorganic films offer barrier properties against moisture and static electricity, while organic films provide additional insulation and flexibility. This composite structure achieves superior protection effectiveness while managing the complexity through material diversity.
Solution Approach 2:
The patent implements segmentation by dividing the protective barrier into multiple discrete film layers, each with specific functions. Rather than using a single thick insulating layer, the protection is segmented into multiple thinner layers of different materials (silicon nitride, silicon oxide, organic resin), allowing each layer to perform its specific protective function while distributing the overall complexity across manageable segments.
Data Source
AI summary
In a frame region closer to a display region than a peripheral circuit is a protective element provided along each display wire. The protective element has the following: a first conductive layer composed of a first semiconductor film made of polysilicon; a third semiconductor layer composed of a second semiconductor film made of an oxide semiconductor, and formed on the first conductive layer with a fifth inorganic insulating film interposed therebetween; and a second conductive layer and a third conductive layer composed of a third metal film, formed so as to be spaced from each other, and electrically connecting the first conductive layer to a first source region and a first drain region.