Multilayer Electrode with Intermediate Conductive Layer
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Solution Overview
Problem
The reliability of electronic devices with multilayer electrodes is compromised due to gaps formed during the etching process, caused by differences in activity between adjacent metal layers, leading to potential corrosion and reduced durability.
Innovation Solution
A multilayer electrode structure is implemented, where a second conductive layer with a chemical electromotive force between the first and third conductive layers prevents direct contact and subsequent oxidation, thereby reducing the formation of gaps and enhancing adhesion, using materials like copper alloy for the second conductive layer and molybdenum or titanium for the first and third layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple metal layers are stacked to form an electrode, then the electrode can be formed with desired electrical properties, but gaps are generated due to difference in activity between adjacent metal layers during etching process
Solution Approach 1:
An intermediate conductive layer is introduced between the first and third conductive layers. This intermediate layer acts as a mediator that prevents direct contact between metal layers with significantly different activities, thereby eliminating the galvanic effect that causes gaps during etching. The intermediate layer has chemical electromotive force values between those of the adjacent layers, ensuring gradual transition and preventing oxidation-induced gaps.
Solution Approach 2:
The electrode structure uses a composite multilayer configuration where each layer is made of different conductive materials with progressively varying chemical electromotive forces. This composite structure combines materials with different properties (copper, copper alloy, molybdenum/titanium) to achieve both electrical performance and manufacturing reliability by preventing gap formation through controlled material transitions.
2Reliability
If metal layers with different activities are stacked, then electrical conductivity can be optimized, but oxidation occurs leading to gap formation and reduced adhesion
Solution Approach 1:
The intermediate conductive layer serves as a protective intermediary that prevents direct oxidation of the copper layer by isolating it from environments that would cause galvanic oxidation. By having intermediate chemical electromotive force values, this layer reduces the oxidation rate of more reactive metal layers while maintaining electrical conductivity and interlayer adhesion.
3Ease of manufacture
If a simple single-layer electrode is used, then manufacturing is simpler, but gaps form during etching due to metal activity differences
Solution Approach 1:
The electrode is segmented into multiple conductive layers with progressively varying chemical electromotive forces. This segmentation allows each layer to have optimized properties while the gradual transition between layers prevents the galvanic effect. The segmentation approach maintains manufacturing feasibility through sequential deposition processes while dramatically improving reliability by eliminating gap formation.
4Object-affected harmful factors
If gaps are formed in the electrode, then moisture penetration increases, but the passivation layer stability is compromised
Solution Approach 1:
The invention converts the potential harm of metal oxidation into a benefit by using the oxidation tendency to create a controlled intermediate layer structure. The intermediate conductive layer with intermediate chemical electromotive force values acts as a barrier that prevents moisture penetration pathways, thereby stabilizing the passivation layer and preventing the harmful effects of gap formation while maintaining the necessary electrical properties.
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 configuration decreases the oxidation rate of the more reactive metal layers, prevents gap formation, and enhances the reliability of the electronic device by ensuring a continuous, gap-free surface, which in turn reduces moisture penetration and improves the stability of the passivation layer.
Implementation Method 1
the metal layer having higher activity often generates gaps because of the difference in activity between the adjacent metal layers in the etching process
Data Source
AI summary
An electronic device is provided. The electronic device includes a first substrate. The electronic device also includes a multilayer electrode disposed on the first substrate. The multilayer electrode includes a first conductive layer, a second conductive layer disposed on the first conductive layer, and a third conductive layer disposed on the second conductive layer. The electronic device further includes a second substrate facing the first substrate. In addition, the electronic device includes a working medium disposed between the first substrate and the second substrate. The chemical electromotive force of the second conductive layer is between that of the first conductive layer and the third conductive layer.