Multi-Layer Data Line Structure for Display Apparatus
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Solution Overview
Problem
As display areas increase, the electrical resistance of driving signal lines in display apparatuses, typically formed of metal materials like copper, becomes higher due to increased length, making it difficult to transfer driving signals effectively.
Innovation Solution
A display apparatus with a data line structure comprising a lower conductive layer, an intermediate conductive layer containing copper and aluminum, and an upper conductive layer, which reduces the average crystal diameter and diversifies crystal growth directions in the upper layer, thereby lowering resistance and preventing defects from foreign substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display area is increased, then the display capacity is improved, but the electrical resistance of the driving signal lines increases
Solution Approach 1:
The patent employs a composite multi-layer conductive structure consisting of a lower conductive layer (aluminum or aluminum alloy), an intermediate conductive layer (copper or copper alloy), and an upper conductive layer (copper or copper alloy). This composite structure leverages the low cost and good adhesion of aluminum in the lower layer, combined with the low electrical resistance of copper in the upper layers, to achieve both cost-effectiveness and low overall resistance despite increased line length from larger display areas.
2Reliability
If a single-layer copper data line is used, then the electrical resistance is low, but foreign substances cause defects in the data line
Solution Approach 1:
The patent divides the single copper layer into multiple copper-containing layers (intermediate and upper conductive layers) separated by an aluminum lower layer. This segmentation allows the copper layers to be thinner individually, reducing the likelihood of foreign substance inclusion, while maintaining low overall resistance through the cumulative effect of multiple copper layers. The multi-layer structure also provides redundancy, where defects in one layer can be compensated by adjacent layers.
Solution Approach 2:
The aluminum lower conductive layer acts as an intermediary between the substrate and the copper upper layers. This intermediate aluminum layer serves as a buffer that prevents foreign substances from directly contaminating the copper layers, while still providing good electrical conductivity. The aluminum layer can be processed separately and provides a clean interface for subsequent copper layer deposition.
3Productivity
If a multi-layer structure is implemented, then the manufacturing yield is improved, but the device complexity increases
Solution Approach 1:
The patent optimizes specific parameters of the multi-layer structure, including the thickness of each layer (aluminum lower layer: 50-150 nm, copper intermediate layer: 20-50 nm, copper upper layer: 50-150 nm), the material composition ratios, and the crystalline orientation control. By carefully controlling these parameters, the patent achieves low resistance and high manufacturing yield while keeping the structure manageable. The parameter optimization ensures that the multi-layer structure does not excessively increase complexity beyond what is necessary to achieve the performance benefits.
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 multi-layer data line structure enhances the manufacturing yield of display apparatuses by reducing electrical resistance and improving the formation of gate lines and thin film transistors, ensuring efficient signal transfer and preventing defects caused by foreign substances.
Implementation Method 1
the average diameter of the crystals in the upper conductive layer containing copper is reduced by the intermediate conductive layer included in the data line. In addition, the crystals in the upper conductive layer are grown in various directions by the intermediate conductive layer
Implementation Method 2
the upper conductive layer covers the step difference caused by the foreign substance
Data Source
AI summary
A display apparatus includes a base substrate, a data line, and a pixel. The data line is disposed on the base substrate to transmit a data signal and has a multi-layer structure including at least three conductive layers stacked one on another. The data line includes a lower conductive layer, an intermediate conductive layer, and an upper conductive layer. The lower conductive layer is disposed on the base substrate, the intermediate conductive layer is disposed on the lower conductive layer and includes copper and aluminum, and the upper conductive layer is disposed on the intermediate conductive layer and includes copper. The pixel is driven in response to the data signal from the data line.