Electro-Optical Device Light Shielding Structure for Gate Insulator Protection
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Solution Overview
Problem
The existing electro-optical devices face a risk of damage to the gate insulating film during the etching process for forming contact holes due to the overlap of the light shielding layer with the gate insulating film, which can lead to operational failures and display defects.
Innovation Solution
The electro-optical device is configured with a first light shielding film on the insulating layer and a second light shielding film between the substrate and the semiconductor layer, where the second light shielding film has a portion overlapping the semiconductor layer and another portion overlapping the first light shielding film at a different position, allowing capacitive coupling to absorb etching-induced electric fields and prevent damage to the gate insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the light shielding layer is positioned to overlap the gate insulating film in plan view, then light shielding effectiveness is improved, but the gate insulating film may be destroyed by etching during contact hole formation
Solution Approach 1:
The light shielding function is divided into two separate layers: a first light shielding layer positioned at the gate electrode level and a second light shielding layer positioned at the substrate level. This segmentation allows each layer to perform light shielding without compromising the gate insulating film, as the second layer does not overlap the gate insulating film in plan view
Solution Approach 2:
The light shielding function is distributed across different vertical dimensions (layers). The first light shielding layer is positioned above the gate electrode while the second light shielding layer is positioned below the semiconductor layer, creating a multi-dimensional light shielding architecture that avoids the harmful overlap with the gate insulating film
2Device complexity
If a single light shielding layer is used, then device complexity is reduced, but light shielding effectiveness and transistor stability are insufficient
Solution Approach 1:
The light shielding function is segmented into two separate layers positioned at different vertical levels, allowing each layer to contribute to overall light shielding effectiveness while maintaining clear spatial separation from sensitive components like the gate insulating film
Solution Approach 2:
Each light shielding layer is positioned to provide light shielding at its specific location: the first layer shields the gate electrode region while the second layer shields the substrate region. This localized approach optimizes light shielding where needed without creating harmful overlaps
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 configuration effectively reduces the risk of gate insulating film damage and operational failures, enhancing display quality by stabilizing transistor operations and reducing display defects.
Implementation Method 1
a second light shielding film provided between the substrate and the semiconductor layer, in which the second light shielding film has a first portion overlapping the semiconductor layer and a second portion overlapping the first light shielding film at a different position from the semiconductor layer when viewed in a normal direction of the substrate
Data Source
AI summary
An electro-optical device includes a substrate, a transistor including a semiconductor layer, a gate insulating film, and a gate electrode that are aligned in a direction away from the substrate, a first insulating layer covering the transistor, a first contact provided at the first insulating layer and coupled to the gate electrode, a first light shielding film provided at the first insulating layer, and a second light shielding film provided between the substrate and the semiconductor layer, in which the second light shielding film has a first portion overlapping the semiconductor layer and a second portion overlapping the first light shielding film at a different position from the semiconductor layer when viewed in a normal direction of the substrate.