Piezoelectric Vibration Device Electrode Segmentation and Laser Cutting
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Solution Overview
Problem
Piezoelectric vibration devices face challenges in maintaining airtight reliability and electrical conduction between the taking out electrode and external electrode due to stress concentration at the boundary of the through hole, leading to potential electrical shorts and reduced reliability.
Innovation Solution
A method involving the formation of a bonding electrode on a piezoelectric substrate, a through hole in a cover with a glass film surrounding the edge of the hole, and anodic bonding to seal the gap, followed by cutting the electrical coupling between the taking out electrode and bonding electrode using laser light to prevent shorts and reduce stress on the external electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external electrode is formed through a through hole in a glass plate bonded to a piezoelectric substrate, then electrical conduction to the taking out electrode is achieved, but stress concentrates at the boundary part of the through hole causing cracks and reducing reliability
Solution Approach 1:
The invention divides the electrode structure into multiple segments: the taking out electrode on the piezoelectric substrate, the external electrode on the glass plate, and a bridge electrode connecting them through the through hole. This segmentation distributes the stress and electrical conduction path, preventing stress concentration at a single boundary point while maintaining electrical reliability.
2Strength
If glass film and silicon substrate are anodically bonded with a through hole for electrode connection, then stress on the external electrode is reduced, but metal at the anodic bonding part and taking out electrode become electrically shorted
Solution Approach 1:
The bridge electrode acts as an intermediary element between the taking out electrode and the external electrode. It provides a controlled electrical connection path through the anodically bonded region, preventing direct shorting while maintaining the stress-reducing benefits of the anodic bonding structure.
3Strength
If the peripheral part of the through hole is anodically bonded to reduce stress, then electrode strength improves, but electrical short occurs between bonding metal and taking out electrode
Solution Approach 1:
The invention extracts or removes the direct electrical connection between the taking out electrode and the anodically bonded peripheral region. By using the bridge electrode configuration, the harmful electrical short path is eliminated while preserving the mechanical strength benefits of the anodic bonding at the through hole periphery.
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 enhances the reliability of airtight sealing and electrical conduction while preventing electrical shorts between the taking out electrode and metal, improving the overall performance of the piezoelectric vibration device.
Implementation Method 1
bonding the first glass film to the taking out electrode as well as the second glass film to the bonding electrode by generating an electric field so that a predetermined potential difference is given between the bonding electrode set as a positive electrode and the first and the second glass films that are set as a negative electrode
Implementation Method 2
cutting the electrical coupling between the taking out electrode and bonding electrode after step (e)
Implementation Method 3
the piezoelectric substrate generating a vibration based on a driving signal input into the exciting electrode
Data Source
AI summary
Manufacturing a piezoelectric vibration device, includes: forming a bonding electrode on a part of a piezoelectric substrate to which a cover makes contact; forming a part defining a through hole to the cover so that a profile of an edge of an opening of the through hole at a first surface of the cover is positioned inside an outer shape of the taking out electrode in a plan view when the cover and the piezoelectric substrate are overlapped; forming a first glass film on the first surface of the cover; forming a second glass film on the first surface of the cover; bonding the first glass film to the taking out electrode as well as the second glass film to the bonding electrode by generating an electric field; and cutting an electrical coupling between the taking out electrode and the bonding electrode after step (e).