Piezoelectric Vibrator Structure With Selective Insulation and Bonding
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Solution Overview
Problem
Existing piezoelectric vibrator devices do not adequately prevent shorting between electrodes, which can lead to performance issues and reliability concerns.
Innovation Solution
A vibrator device design featuring a semiconductor substrate with an insulating film over the excitation electrode and direct bonding of a silicon cover to the substrate, ensuring the insulating film is absent at the joint portion to prevent shorting and maintain a reduced pressure environment for improved oscillation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating film is disposed over the excitation electrode to prevent shorting, then reliability is improved, but the insulating film may interfere with the bonding between the semiconductor substrate and the cover
Solution Approach 1:
The insulating film is selectively disposed only in regions where electrode shorting prevention is needed, while being absent at the bonding area between the semiconductor substrate and cover. This local differentiation allows the film to provide insulation where required without interfering with the bonding process.
Solution Approach 2:
The insulating film coverage is segmented into distinct regions: covered areas over the excitation electrode for insulation, and uncovered areas at the bonding portion for proper substrate-cover bonding. This segmentation resolves the contradiction by spatially separating the insulation function from the bonding function.
2Ease of manufacture
If the insulating film is absent at the joint portion to enable proper bonding, then ease of manufacture is improved, but shorting between electrodes may occur
Solution Approach 1:
The insulating film presence is locally differentiated: absent at the joint portion to enable bonding, and present over the electrode areas to prevent shorting. This local quality variation allows both bonding and insulation requirements to be satisfied simultaneously.
3Productivity
If a compact package design is implemented to reduce device size, then productivity is improved, but heat strain increases affecting oscillation efficiency
Solution Approach 1:
The package design utilizes parameter optimization where the insulating film's selective placement and material properties are adjusted to manage heat distribution. The film's presence in certain areas and absence in others creates thermal management characteristics that reduce heat strain while maintaining compact dimensions.
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 shorting between electrodes, enhances the reliability of the vibrator device, and allows for a compact package with reduced heat strain, improving oscillation efficiency and device performance.
Implementation Method 1
an insulating film being disposed over a portion of the excitation electrode in plan view
Implementation Method 2
a piezoelectric vibrator that includes: a sealed container formed of a base member and a cover member that are bonded to each other via a metal film; a piezoelectric vibrator element housed inside the sealed container
Data Source
AI summary
A vibrator device includes a semiconductor substrate, a vibrator unit, a cover, and an insulating film. The vibrator unit is disposed at a first surface of the semiconductor substrate, and includes a vibrator element, and an excitation electrode disposed at the vibrator element and having a portion facing the semiconductor substrate. The cover is bonded to the first surface in a joint portion surrounding the vibrator unit. The insulating film is disposed at the first surface. The insulating film overlaps the portion of the excitation electrode in plan view, and is absent at the joint portion of the semiconductor substrate and the cover.