Piezoelectric Acoustic Wave Package Insulation for DC Leakage
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Solution Overview
Problem
Existing packaged multi-layer piezoelectric substrate acoustic wave devices suffer from direct current (DC) leakage, which degrades device performance and affects the amplification of weak signals in low noise amplifiers.
Innovation Solution
Incorporating an insulator along the electrical pathway and between the support substrate and the cap structure, using materials like silicon oxide and polycrystalline silicon to prevent DC leakage, and employing a dielectric cap substrate with similar thermal expansion to the support substrate to minimize structural stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrical pathway is provided between the acoustic wave element and terminal through the support substrate, then electrical connection is achieved, but DC leakage occurs through the support substrate
Solution Approach 1:
An insulator is introduced as an intermediary component between the electrical pathway and the support substrate. The insulator prevents DC leakage while allowing the electrical pathway to maintain its connection function, thus resolving the contradiction between achieving reliable electrical connection and preventing harmful DC leakage.
Solution Approach 2:
The support substrate is segmented into functional regions: a first region containing the electrical pathway and a second region containing the insulator. This segmentation allows the electrical pathway to provide connection while the insulator region prevents DC leakage, enabling both functions to coexist without interference.
2Reliability
If a cap structure is coupled to the multi-layer piezoelectric substrate, then device protection and sealing are improved, but thermal stress is generated due to coefficient of thermal expansion mismatch
Solution Approach 1:
The coefficient of thermal expansion of the cap structure is adjusted to match that of the support substrate. By changing this material parameter, thermal stress is minimized during temperature variations, allowing the cap structure to provide protection and sealing without generating harmful stress.
3Object-generated harmful factors
If the insulator is positioned between the support substrate and electrical pathway, then DC leakage is reduced, but device complexity increases
Solution Approach 1:
The insulator is merged with the support substrate structure, where the support substrate's first region provides electrical connection and the second region provides insulation. This integration reduces the number of separate components and simplifies the overall device structure while maintaining DC leakage reduction.
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 DC leakage, ensuring reliable signal amplification and improved device performance by maintaining the integrity of the electrical pathway and reducing thermal stress.
Implementation Method 1
an insulator between the support substrate and the electrical pathway
Implementation Method 2
employing a dielectric cap substrate with similar thermal expansion to the support substrate to minimize structural stress
Data Source
AI summary
A packaged multi-layer piezoelectric substrate acoustic wave device with reduced DC leakage is disclosed. The packaged acoustic wave device can include a multi-layer piezoelectric substrate acoustic wave device and a cap structure. The multi-layer piezoelectric substrate acoustic wave device includes a support substrate, a piezoelectric layer, and an acoustic wave element. The packaged acoustic wave device can include a terminal that can be connected to the acoustic element through an electrical pathway. The terminal can be provided with the multi-layer piezoelectric substrate acoustic wave device or with the cap structure. The packaged acoustic wave device can include an insulator that can prevent or suppress the DC leakage from the electrical pathway. The electrical pathway can include a via formed in the support substrate of the multi-layer piezoelectric substrate, a via formed in a cap substrate of the cap structure, a conductive layer, or a conductive pillar.