Copper Alloy Electrodes with Oxide Layer for LCD TFT Stability
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Solution Overview
Problem
Conventional techniques for copper interconnections in liquid crystal display (LCD) devices face challenges such as oxidation, poor adhesiveness to glass substrates, and increased electrical resistance, which affect the stability and performance of thin film transistor (TFT) electrodes, particularly for source and drain electrodes.
Innovation Solution
A copper alloy layer, such as Cu-Mn, is used with an oxide layer formed by heat treatment, which covers the electrodes and ensures adhesiveness to semiconductor layers and pixel electrodes, preventing oxidation and maintaining low electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multilayer structure (Ti/Al/Ti or Mo/Al/Mo) is used to prevent hillocks and migrations, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses a composite structure of copper layer plus alloy layer that provides stability against hillocks and migrations without requiring complex multilayer configurations. The alloy layer specifically designed with elements like Mn, Al, or Si achieves the desired stability while simplifying the overall manufacturing process compared to traditional Ti/Al/Ti or Mo/Al/Mo structures.
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 provides stable, low-resistance interconnections with improved adhesiveness and oxidation resistance, enabling efficient operation of TFT structures in LCD devices by forming a manganese oxide layer that prevents copper diffusion and maintains a linear current-voltage relationship.
Implementation Method 1
an oxide layer, which covers the electrodes and ensures adhesiveness to semiconductor layers and pixel electrodes, preventing oxidation
Implementation Method 2
an oxide layer formed by heat treatment
Implementation Method 3
forming a manganese oxide layer that prevents copper diffusion
Implementation Method 4
securing the adhesiveness to the glass substrate by reaction of alloy elements with the substrate forming a layer at their interface
Data Source
AI summary
In a liquid crystal display (LCD) device having a thin film transistor (TFT), the TFT includes a source electrode, a drain electrode and a semiconductor layer. At least one of the source electrode and drain electrode includes a first layer including copper and a second layer forming an oxide layer and covering the first layer. The semiconductor layer has a substantially linear current-voltage relationship with said source electrode or drain electrode including said first and second layers, when a voltage is applied between the semiconductor layer and said source electrode or drain electrode.