Silicon Resonator Surface Tuning for Stable Frequency Adjustment
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Solution Overview
Problem
Existing resonance devices face challenges in adjusting resonant frequency due to thermal or stress loads applied during production, leading to frequency fluctuations.
Innovation Solution
A resonance device is designed with a lower cover made of non-degenerate silicon and a resonator made of degenerate silicon, featuring a multilayer structure with a piezoelectric film and adjustment films, allowing for precise adjustment of resonant frequency through laser irradiation of the substrate surface to form adjustment portions with varying projections and recesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resonant frequency is adjusted by changing film thicknesses during manufacturing, then resonant frequency can be tuned, but frequency fluctuates due to thermal or stress loads in subsequent production steps
Solution Approach 1:
The patent applies preliminary action by pre-forming adjustment portions (protrusions or recesses) on the lower surface of the resonator substrate before packaging. These adjustment portions are created through laser irradiation that selectively removes material, allowing frequency adjustment to be performed in advance before thermal or stress loads from subsequent production steps can cause fluctuations. This ensures frequency stability while maintaining adjustment capability.
Solution Approach 2:
The patent utilizes parameter changes by modifying the physical structure of the substrate through laser irradiation. The laser energy causes localized melting and removal of silicon material, changing the thickness parameter of the substrate in specific regions. This creates adjustment portions that alter the resonator's mechanical properties and enable precise frequency tuning without affecting overall structural integrity.
2Manufacturing precision
If laser irradiation is used to form adjustment portions on the substrate surface, then resonant frequency can be precisely adjusted after packaging, but requires specialized manufacturing process
Solution Approach 1:
The patent replaces traditional mechanical adjustment methods with laser irradiation. Instead of using mechanical tools to remove or add material to the substrate, a laser beam is used to selectively vaporize and remove silicon material from the lower surface. This substitution enables more precise control over the adjustment portions and allows frequency tuning to be performed after packaging, overcoming the limitations of mechanical methods.
Solution Approach 2:
The patent exploits phase transitions of silicon under laser irradiation. The laser energy causes localized melting and subsequent vaporization of the silicon substrate material. This phase transition from solid to liquid to gas enables precise removal of material in controlled amounts, creating the adjustment portions needed for frequency tuning with high precision.
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 approach enables stable and precise adjustment of resonant frequency after packaging, preventing frequency fluctuations caused by thermal or stress loads, thereby enhancing the device's performance and reliability.
Implementation Method 1
a piezoelectric film formed between the first electrode layer and the second electrode layer
Implementation Method 2
adjustment portions that are regions where a depth or height of projections and recesses formed on the surface is larger than that in another region
Data Source
AI summary
A resonance device that includes a lower cover formed from non-degenerate silicon; a resonator having a degenerate silicon substrate with a lower surface facing the lower cover, and including first and second electrode layers laminated on the substrate with a piezoelectric film formed therebetween and having a surface opposing an upper surface of the substrate. Moreover, the lower surface of the substrate has an adjustment region where a depth or height of projections and recesses formed on the surface is larger than that in another region of the lower surface of the substrate or is a region where an area of the projections and recesses is larger than that in the other region of the lower surface of the substrate.