Non-overlapping Contact Holes in Multi-layer Pad Structure
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Solution Overview
Problem
The miniaturization of flat panel displays leads to insufficient design margins, resulting in increased contact resistance and disconnection defects due to misalignment of contact holes during the manufacturing process, particularly in the integration of data and gate driving integrated circuits.
Innovation Solution
A pad structure with multiple metal layers and non-overlapping contact holes in insulating layers, ensuring a sufficient design margin by separating the first and second contact holes and optimizing their locations to prevent alignment errors and steep steps, thereby reducing contact resistance and disconnection defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If contact holes are minimized to reduce design margin requirements, then manufacturing complexity is reduced, but contact resistance increases and alignment precision deteriorates
Solution Approach 1:
The patent introduces a temporal dimension to the contact hole formation process by performing multiple etching operations at different time points. First contact holes are formed, then second contact holes are formed later in the process. This temporal separation allows each contact hole to be precisely aligned independently, solving the alignment precision problem while maintaining minimized contact hole dimensions.
Solution Approach 2:
The contact hole formation process is segmented into multiple independent steps: first contact holes are formed through the first insulating layer, then second contact holes are formed through the second insulating layer. This segmentation allows each contact hole to be optimized and aligned separately, preventing the accumulation of alignment errors that would occur in a single-step process.
2Area of moving object
If contact holes are minimized to reduce design margin, then area is reduced, but contact resistance increases
Solution Approach 1:
The patent adds a vertical dimension to the contact hole structure by forming contact holes through multiple insulating layers at different depths. The first contact holes penetrate the first insulating layer to expose the first electrode, while second contact holes penetrate the second insulating layer to expose the second electrode. This multi-level contact hole arrangement reduces the lateral area of each contact hole while maintaining adequate contact resistance through proper vertical positioning and electrode exposure.
Data Source
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AI summary
Disclosed is a display device, comprising a plurality of signal lines arranged in a display area of a substrate and a pad structure located at a non-active area and connected with the signal lines, wherein the pad structure comprises two or more metal layers and an insulating layer located between the metal layers and having one or more contact hole which makes two metal layers among the metal layers contacted with each other, and the contact holes respectively located in the insulating layers are not overlapped with each other.