Active Device Array Substrate Copper Layer Acute Trapezoid Design
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Solution Overview
Problem
Large panel sizes of thin film transistor liquid crystal displays (TFT-LCD) face signal distortion due to RC delay effects caused by high resistance in metal wires, and copper oxide formation during etching leads to wire disconnection issues.
Innovation Solution
A patterned conductive layer with a copper layer having acute trapezoidal cross-sections and a barrier layer, where the base angles of the trapezoids differ by 5° to 30°, is used, and a two-step deposition method with varying rates to reduce oxidation and improve atom arrangement, preventing structural defects and wire disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single layer of copper is used as metal wire to reduce resistance, then RC delay effects are reduced, but copper oxide formation during etching causes wire disconnection
Solution Approach 1:
The patent uses a composite copper layer structure with two distinct copper layers having different base angles (first copper layer: 45-75°, second copper layer: 15-45°). This composite structure prevents copper oxide formation during etching while maintaining low resistance, thereby resolving the contradiction between wire connection reliability and copper oxide formation harm
Solution Approach 2:
The patent applies different deposition conditions to different parts of the copper layer structure. The first copper layer is deposited with a first deposition rate to achieve a specific base angle range (45-75°), while the second copper layer is deposited with a second deposition rate to achieve a different base angle range (15-45°). This local differentiation in deposition quality prevents copper oxide formation while maintaining overall low resistance
2Area of stationary object
If panel size is enlarged to increase display area, then display quality improves, but resistance values of metal wires increase causing RC delay effects
Solution Approach 1:
The composite copper layer structure with optimized base angles creates a more efficient conductive path that compensates for the increased resistance due to larger panel sizes. The dual-layer structure with different base angles reduces overall resistance, allowing larger panels to maintain signal transmission quality and avoid RC delay effects
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
The solution effectively reduces wire disconnection rates and enhances electrical characteristics by improving the exterior structure and reducing thin film defects, leading to better display quality and reliability.
Implementation Method 1
a first copper layer is deposited at a first deposition rate on a substrate. Next, a second copper layer is deposited at a second deposition rate on the first copper layer
Data Source
AI summary
An active device array substrate has at least one patterned conductive layer. The patterned conductive layer includes a copper layer. A cross-section of the copper layer which is parallel to a normal line direction of the copper layer includes a first trapezoid and a second trapezoid stacked on the first trapezoid. A base angle of the first trapezoid and a base angle of the second trapezoid are acute angles, and a difference between the base angle of the first trapezoid and the base angle of the second trapezoid is from about 5° to about 30°.