Acoustic Wave Device Ceramic Sealing Process
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Solution Overview
Problem
Conventional acoustic wave devices require multiple fabrication processes, increasing production costs and compromising moisture resistance, heat release performance, and power durability due to resin sealing.
Innovation Solution
An acoustic wave device is fabricated using a substrate with a functional element, columnar electrode, and metal frame body, where a ceramic substrate is stacked to form both a terminal portion and a sealing portion, simultaneously sealing the functional element and establishing electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin sealing is used to seal the acoustic wave chip, then the sealing process is simple, but the moisture resistance, heat release performance, and power durability are compromised
Solution Approach 1:
The patent changes the material parameter of the sealing structure from resin to ceramic substrate. The ceramic substrate provides superior moisture resistance, heat release performance, and power durability compared to resin, while maintaining ease of manufacture through the integrated fabrication process that forms metal layers directly on the ceramic substrate during the same process that creates the columnar electrodes and metal frame body.
2Reliability
If separate processes are used for connecting signal terminals and hermetically sealing the acoustic wave chip, then the connections are reliable, but the number of fabrication processes increases and production cost increases
Solution Approach 1:
The patent merges the terminal connection process and the hermetic sealing process into a single integrated fabrication process. The metal layers are formed on the ceramic substrate in the same process that creates the columnar electrodes and metal frame body, eliminating the need for separate connection and sealing steps. This reduces the number of fabrication processes while maintaining reliable electrical connections through the directly-formed metal layers.
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 method reduces the number of fabrication processes, enhances moisture resistance, heat release, and power durability by using a ceramic substrate for sealing instead of resin, improving overall device reliability and reducing production costs.
Implementation Method 1
a first metal layer bonded to the columnar electrode and a second metal layer bonded to the metal frame body being formed on a surface of the ceramic substrate
Data Source
AI summary
An acoustic wave device includes: a substrate; a functional element formed on the substrate and including an excitation electrode that excites an acoustic wave; a columnar electrode formed on the substrate and electrically connected to the excitation electrode; a metal frame body formed on the substrate and surrounding the functional element and the columnar electrode; and a ceramic substrate sealing the functional element in combination with the metal frame body, a first metal layer bonded to the columnar electrode and a second metal layer bonded to the metal frame body being formed on a surface of the ceramic substrate.