Acoustic Wave Shielding Structure for EMI Isolation and Bonding Reliability
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Solution Overview
Problem
Existing acoustic wave devices, such as SAW and BAW filters, face challenges in effectively shielding electromagnetic waves and preventing external interference during manufacturing, which can lead to performance issues and reliability concerns.
Innovation Solution
The proposed acoustic wave device incorporates a shielding member electrically connected to a ground terminal through a support part and sealing part, ensuring proper spacing and protection of the acoustic wave generating part, while the ground terminal is bonded to the shielding member, enhancing bonding reliability and preventing external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shielding member is added to block electromagnetic waves, then electromagnetic shielding effectiveness is improved, but device complexity increases
Solution Approach 1:
The support part serves dual functions: mechanically supporting the shielding member and providing electrical connection to ground terminal. The ground terminal itself serves both as electrical connection point and as part of the grounding path for electromagnetic shielding. This multi-functionality reduces the need for separate dedicated components, thereby improving shielding effectiveness without proportionally increasing device complexity.
Solution Approach 2:
The patent combines the support structure and the grounding connection into a unified support part that performs both mechanical support and electrical connection functions. The shielding member is integrated with the support part and ground terminal to form a combined electromagnetic shielding and grounding system, reducing overall component count and simplifying the device structure while maintaining effective electromagnetic shielding.
2Reliability
If proper spacing is maintained between acoustic wave generating part and shielding member, then acoustic wave performance is preserved, but manufacturing precision requirements increase
Solution Approach 1:
The support part is designed with predetermined spacing dimensions that are established during the manufacturing process. The support part acts as a pre-configured spacer that automatically maintains the required distance between the acoustic wave generating part and shielding member, eliminating the need for complex post-assembly adjustments and reducing the actual precision requirements during final assembly.
Solution Approach 2:
The support part serves as an intermediary element between the acoustic wave generating part and the shielding member. This intermediate component absorbs the spacing requirements, providing a buffer zone that ensures proper separation while simplifying the manufacturing process. The support part can be manufactured with standard tolerances and still achieve the required spacing precision through its design geometry.
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 effectively shields electromagnetic waves, maintains the acoustic wave device's performance by preventing external interference and ensuring reliable operation, and simplifies the manufacturing process by allowing easy connection of the shielding member to the ground terminal.
Implementation Method 1
The ground terminal may include a solder bump or a solder ball.
Implementation Method 2
Piezoelectric characteristics of the deposited IDT electrode or the piezoelectric dielectric material are used to cause resonance.
Data Source
AI summary
An acoustic wave device includes: a substrate; an acoustic wave generating part disposed on a surface of the substrate; a ground pad disposed on the surface of the substrate; a support part spaced apart from the acoustic wave generating part on the surface of the substrate; a shielding member disposed on the support part, and spaced apart from the acoustic wave generating part; and a ground terminal disposed on the ground pad, wherein the ground pad and the shielding member are electrically connected to each other through the ground terminal.