Bulk Acoustic Wave Filter Lower Electrode Reinforcement
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Solution Overview
Problem
Current bulk acoustic wave filter devices face challenges in maintaining consistent electrical characteristics due to damage and loss of the lower electrode during manufacturing processes, which affects the filter's performance and miniaturization efforts in RF components.
Innovation Solution
The introduction of a lower electrode reinforcing layer, formed from the same material as the lower electrode, which is separated from the upper electrode or frame layer during manufacturing, prevents loss and damage, thereby maintaining the electrical characteristics of the bulk acoustic wave filter device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the lower electrode is manufactured using conventional semiconductor thin film processes, then the filter can be miniaturized, but the lower electrode suffers from damage and loss during manufacturing, affecting electrical characteristics
Solution Approach 1:
The lower electrode reinforcing layer is formed in advance before the piezoelectric layer is deposited, providing structural support and protection to the lower electrode during subsequent manufacturing processes. This preliminary reinforcement prevents damage and loss that would otherwise occur during conventional semiconductor thin film processes.
Solution Approach 2:
The lower electrode reinforcing layer acts as a protective cushion that absorbs mechanical stress and prevents damage to the lower electrode during manufacturing. This beforehand cushioning ensures the lower electrode maintains its integrity throughout the fabrication process, preserving electrical characteristics consistency.
2Reliability
If the lower electrode reinforcing layer is formed by separating it from the upper electrode or frame layer, then the manufacturing process becomes more complex, but the lower electrode is protected from loss and damage
Solution Approach 1:
The lower electrode reinforcing layer is formed as a separate, distinct layer that can be independently patterned and separated from the upper electrode or frame layer. This segmentation allows for simplified manufacturing where each layer can be processed independently, reducing overall process complexity while maintaining reliability.
Solution Approach 2:
The lower electrode reinforcing layer serves as an intermediary structure between the lower electrode and the upper electrode/frame layer. This intermediary layer provides the necessary mechanical support and protection without requiring complex integrated structures, enabling straightforward separation and manufacturing.
3Stability of the object's composition
If the lower electrode reinforcing layer is formed of the same material as the lower electrode, then material compatibility is improved, but additional manufacturing steps are required
Solution Approach 1:
The lower electrode reinforcing layer is formed using the same material as the lower electrode, creating a homogeneous structure with identical material properties. This homogeneity ensures perfect material compatibility, thermal expansion matching, and electrical conductivity throughout the electrode assembly, eliminating interface issues.
Solution Approach 2:
The formation of the lower electrode and lower electrode reinforcing layer is combined into a single deposition process using the same material. This merging of material types simplifies the overall manufacturing approach, even though additional patterning steps are required, by eliminating the need for material transitions and interface management.
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 solution enhances the stability and performance of the bulk acoustic wave filter device by preventing loss and damage to the lower electrode, ensuring consistent electrical characteristics and supporting the miniaturization of RF components.
Implementation Method 1
a piezoelectric dielectric material is deposited on a silicon wafer, which is a semiconductor substrate, to produce resonance by using piezoelectric characteristics of the piezoelectric dielectric material as the filter
Data Source
AI summary
A bulk acoustic wave filter device and method thereof includes a first layer forming an air gap together with a substrate, a lower electrode disposed over the first layer, a piezoelectric layer disposed to cover a portion of the lower electrode, an upper electrode disposed over the piezoelectric layer, a frame layer disposed below the upper electrode, and a lower electrode reinforcing layer disposed on the lower electrode, other than portions in which the piezoelectric layer is disposed. The lower electrode reinforcing layer is formed by separating the lower electrode reinforcing layer from the upper electrode or the frame layer upon one of the upper electrode and the frame layer being formed.