Interlayer Insulating Layer Segmentation for Display Contact Holes
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Solution Overview
Problem
The challenge in display device manufacturing is the occurrence of short circuits due to surface steps on insulating layers and the difficulty in forming contact holes, especially when the organic layer is not flat, leading to connection failures between layers.
Innovation Solution
A display device design featuring an interlayer-insulating layer with distinct height portions, where the contact hole is formed in the lower portion, allowing for a flat surface and preventing short circuits, and a manufacturing method involving polishing to create these height differences, ensuring accurate contact hole formation without increasing the contact hole's planar area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the organic layer is made thick to ensure insulation, then insulation performance is improved, but it becomes difficult to form contact holes for connection between layers
Solution Approach 1:
The interlayer insulating layer is divided into multiple portions with different heights (first portion, second portion, third portion). This segmentation allows contact holes to be formed in the lower first portion where the insulating layer is thinner, while the higher second and third portions maintain adequate insulation thickness, thus resolving the contradiction between insulation performance and contact hole formation ease.
Solution Approach 2:
Different portions of the interlayer insulating layer are given different local qualities in terms of height. The first portion has a lower height to facilitate contact hole formation, while the second and third portions have higher heights to ensure insulation. This local differentiation allows each region to optimize for its specific function, solving the contradiction between these two requirements.
2Reliability
If the surface of the insulating layer is made flat to prevent short circuits, then electrical reliability is improved, but manufacturing complexity increases due to additional polishing steps
Solution Approach 1:
The interlayer insulating layer is segmented into portions of different heights, with each upper surface (of the first, second, and third portions) being flat. This segmentation allows the flat surface requirement to be met in each portion through selective polishing, preventing short circuits while managing manufacturing complexity by focusing polishing efforts on specific areas rather than the entire structure.
Solution Approach 2:
The interlayer insulating layer is formed with predetermined height differences before subsequent manufacturing steps. This preliminary structuring with different heights allows for more efficient polishing operations, as the flat surfaces are already partially established by the height differentiation, reducing the overall manufacturing complexity compared to polishing a uniformly thick layer.
3Reliability
If contact holes are formed in thick insulating layers, then connection between layers is achieved, but the planar area of contact holes must be increased which consumes more space
Solution Approach 1:
The interlayer insulating layer is segmented into a first portion (lower height) and second/third portions (higher height). Contact holes are formed specifically in the first portion where the insulating layer is thinner, allowing for adequate connection reliability with smaller planar areas. The second and third portions maintain their height to ensure insulation, thus resolving the contradiction between connection reliability and space consumption.
Solution Approach 2:
The local quality of the insulating layer height is differentiated to create a first portion with reduced thickness for contact hole formation. This local reduction in thickness allows contact holes to achieve reliable connections with smaller planar areas, while the rest of the structure maintains adequate insulation thickness, thereby reducing overall space consumption.
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 effectively prevents wire short circuits and ensures reliable connections through the contact holes, enhancing the manufacturing process by maintaining a flat surface for conductor placement and reducing defects in the display device.
Implementation Method 1
The first portion and the second portion may be polished
Data Source
AI summary
A display device includes: a substrate; a first signal line and a second signal line disposed on the substrate; and an interlayer-insulating layer disposed between the first signal line and the second signal line. The interlayer-insulating layer includes a first portion and a second portion having different heights measured from a surface of the substrate along a first direction that is perpendicular to the surface of the substrate, an upper surface of the first portion of the interlayer-insulating layer is flat, a surface of the second portion of the interlayer-insulating layer is flat, a height of the first portion is lower than a height of the second portion, the interlayer-insulating layer defines a contact hole, and the contact hole is disposed in the first portion of the interlayer-insulating layer.