Multilayer Antenna Electrode Structure for Thermal Expansion Mismatch
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Solution Overview
Problem
Existing antenna devices face issues due to differences in thermal expansion coefficients between metal electrodes and passivation layers, leading to microcracks and corrosion, which affect their stability and operational reliability.
Innovation Solution
A multilayer electrode structure is introduced, comprising a first conductive layer, a second conductive layer, and a third conductive layer that acts as a buffer to cover the second conductive layer, thereby reducing the risk of microcracks and corrosion by improving adhesion and matching thermal expansion coefficients between the passivation layer and the electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single metal electrode layer is used, then the device structure is simple, but microcracks form easily due to thermal expansion mismatch with the passivation layer
Solution Approach 1:
The single electrode layer is divided into multiple conductive layers (first conductive layer, second conductive layer, and third conductive layer) with different thermal expansion coefficients. This segmentation allows each layer to compensate for thermal stress, preventing microcrack formation in the passivation layer while maintaining structural simplicity through a systematic multi-layer approach.
Solution Approach 2:
The electrode structure uses composite material design by combining multiple conductive materials with different thermal expansion properties. The first conductive layer (e.g., Mo, W), second conductive layer (e.g., Al, Cu), and third conductive layer (e.g., Ti, Cr) form a composite structure that bridges the thermal expansion gap between the substrate and passivation layer, enhancing reliability without significant complexity increase.
2Ease of manufacture
If metal electrode and passivation layer are directly combined, then manufacturing is simple, but corrosion occurs due to adhesion failure from thermal expansion differences
Solution Approach 1:
The direct interface between metal electrode and passivation layer is segmented into multiple intermediate conductive layers. Each layer serves as a transition zone with graded thermal expansion properties, preventing adhesion failure and corrosion while maintaining a manufacturable multi-step deposition process.
Solution Approach 2:
The first, second, and third conductive layers act as intermediary layers between the substrate and passivation layer. These intermediate layers mediate the thermal expansion mismatch, providing gradual transition that prevents adhesion failure and corrosion, while the manufacturing process remains straightforward using sequential deposition techniques.
3Device complexity
If thermal expansion mismatch is not addressed, then device structure remains simple, but operational reliability decreases due to microcrack formation
Solution Approach 1:
The thermal expansion parameter is systematically changed across the conductive layers by selecting materials with progressively different thermal expansion coefficients. The first conductive layer has lower thermal expansion, the second has intermediate expansion, and the third has higher expansion, creating a gradient that matches the passivation layer and prevents microcracks while maintaining operational reliability.
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 multilayer electrode structure enhances the stability and reliability of electronic devices by reducing microcrack formation and corrosion, ensuring better protection and performance of the antenna devices.
Implementation Method 1
a thermal expansion coefficient of the second conductive layer is between a thermal expansion coefficient of the first conductive layer and a thermal expansion coefficient of the passivation layer
Data Source
AI summary
An electronic device is provided. The electronic device includes a first substrate, a multilayer structure, and a passivation layer. The multilayer structure is disposed on the first substrate. The multilayer structure includes a first conductive layer and a second conductive layer disposed on the first conductive layer. The passivation layer is disposed on the second conductive layer. In addition, a thermal expansion coefficient of the second conductive layer is between a thermal expansion coefficient of the first conductive layer and a thermal expansion coefficient of the passivation layer.