Piezoelectric Vibrator Through-Electrode Layout for Stress Relief
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Solution Overview
Problem
Piezoelectric vibrator devices face stress concentration issues in through holes due to external forces during mounting, leading to potential breakage and airtightness failure.
Innovation Solution
A vibrator device design featuring a substrate structure with through electrodes having specific outer shapes and bonding members that reduce stress concentration, including a bonding step using metal bonding members with gaps to stabilize dry etching and prevent breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through hole is formed in the first sealing member for electrical coupling, then electrical connection between the piezoelectric vibration plate and IC chip is achieved, but stress concentration occurs in the through hole during mounting, leading to potential breakage
Solution Approach 1:
The through electrode is designed with different curvatures at different portions: the first portion (closer to the cavity) has a smaller curvature radius while the second portion (farther from the cavity) has a larger curvature radius. This local differentiation of geometric properties optimizes both electrical coupling performance and stress distribution, preventing breakage at the more vulnerable first portion while maintaining effective electrical connection.
2Ease of manufacture
If the through hole has a simple circular shape, then manufacturing is simplified, but stress concentrates at the outer shape portion close to the internal space, making the through hole easily broken
Solution Approach 1:
The through electrode employs a non-uniform curvature design where the first portion has a smaller curvature radius and the second portion has a larger curvature radius. This localized variation in geometric properties maintains manufacturing feasibility while significantly improving stress distribution and structural reliability during the mounting process.
Data Source
AI summary
A vibrator device includes: an element substrate including a frame portion having a first surface and a second surface, and a vibrator element disposed inside the frame portion; a first substrate having a third surface and a fourth surface, the first substrate being bonded to the first surface of the frame portion at the third surface; a second substrate having a fifth surface and a sixth surface, the second substrate being bonded to the second surface of the frame portion at the fifth surface; and a cavity surrounded by the frame portion, the first substrate, and the second substrate. The second substrate includes a through electrode at a position overlapping the frame portion in the plan view. An outer shape of the through electrode in the sixth surface in the plan view includes a first portion and a second portion. The first portion is located at a position closer to the cavity than is the second portion. A curvature of the first portion is smaller than a curvature of the second portion.