Active Matrix Substrate Connecting Portion Contact Resistance
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Solution Overview
Problem
Existing active matrix substrates face issues with increased contact resistance at connecting portions due to inadequate coverage of upper conductive films, leading to potential electrical disconnection and high contact resistance, which conventional solutions fail to adequately address.
Innovation Solution
The active matrix substrate incorporates a structure with a lower conductive layer, a first insulating layer with a contact hole, a bottom conductive film covering the exposed part of the lower conductive layer, a second insulating layer covering the bottom conductive film, and an upper conductive layer in contact with the bottom conductive film, effectively reducing contact resistance by improving coverage and reducing the contact hole height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact hole is made deep to connect conductive layers, then the insulation between layers is improved, but the upper conductive film coverage is reduced causing breaking and high contact resistance
Solution Approach 1:
The patent introduces a side wall conductive film formed on the inner wall of the contact hole, adding a vertical dimensional component to the conduction path. This side wall film works in conjunction with the bottom conductive film to provide multiple conduction pathways, ensuring reliable electrical connectivity even when the upper conductive film has reduced coverage at the contact hole opening.
Solution Approach 2:
The side wall conductive film acts as an intermediary element between the upper and lower conductive films. It provides a bridging conduction path that compensates for the reduced coverage of the upper conductive film, ensuring continuous electrical connection through the deep contact hole without requiring the upper film to fully bridge the gap.
2Quantity of substance
If the upper conductive film is made thinner to reduce material usage, then the manufacturing cost is reduced, but the coverage is insufficient leading to breaking and contact resistance increase
Solution Approach 1:
By forming a side wall conductive film on the vertical inner surface of the contact hole, the patent creates an additional conduction dimension. This allows the use of thinner upper conductive films while maintaining reliable electrical connectivity through the combination of bottom and side wall conduction paths, thereby reducing overall conductive material usage.
Solution Approach 2:
The side wall conductive film provides localized conduction capability specifically at the contact hole region where it is most needed. This localized approach allows the upper conductive film to be thinner in non-critical areas while maintaining sufficient coverage and connectivity where the side wall film provides supplemental conduction support.
3Reliability
If the contact hole depth is increased to improve layer separation, then the insulation performance is improved, but the upper conductive film breaking risk increases
Solution Approach 1:
The side wall conductive film provides a vertical conduction path along the contact hole inner wall, creating an alternative route for electrical connection that does not rely solely on the horizontal bridging capability of the upper conductive film. This enables deeper contact holes with better insulation while maintaining conductive film integrity through the side wall support path.
Solution Approach 2:
The side wall conductive film is formed in advance during the manufacturing process, providing pre-established conduction pathways before the upper conductive film is deposited. This preliminary conduction structure ensures that even if the upper film has reduced coverage or breaks, the electrical connection is already secured through the side wall and bottom conductive films.
Data Source
AI summary
An active matrix substrate (1001) includes a connecting portion (101). The connecting portion. (101) includes a lower conductive layer supported by a substrate; a first insulating layer formed so as to cover the lower conductive layer (2) and having a contact hole (6p) that exposes a part of the lower conductive layer (2); a bottom conductive film (4) that is disposed in the contact hole (6p) and covers at least a part of the exposed part of the lower conductive layer (2), the exposed part being exposed by the contact hole (6p); a second insulating layer (9) that is formed on the first insulating layer (6) and in the contact hole (6p), is in contact with the bottom conductive film (4) in the contact hole (6p), and has an opening (9p) that exposes a part of the bottom conductive film (4); and an upper conductive layer (8) that is disposed on the second insulating layer (9) and in the opening (9p) and is in contact with the bottom conductive film (4) in the opening (9p). The entire bottom conductive film (4) is located on the substrate side relative to the upper surface of the first insulating layer (6).