Piezoelectric Device Through-Hole Fabrication via Substrate Segmentation
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Solution Overview
Problem
The existing methods for forming through-holes in bonded piezoelectric devices are time-consuming and prone to microcrack generation, which affects the temperature characteristics and resonant frequency stability.
Innovation Solution
A manufacturing method where the first substrate with a piezoelectric material is bonded to a second substrate with higher toughness, using different methods for forming through-holes in each substrate, such as reactive ion etching for the first substrate and sandblast for the second, to reduce processing time and prevent microcracks, while improving adhesion strength and minimizing thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a through-hole is formed through a bonded piezoelectric substrate using conventional methods, then the through-hole is created, but microcracks are generated and processing time increases
Solution Approach 1:
The through-hole formation process is segmented into two separate operations: first forming a through-hole through the piezoelectric substrate, then forming a second through-hole through the bonded substrate. This segmentation allows each substrate to be processed with its optimal method, preventing microcracks in the brittle piezoelectric substrate while maintaining efficiency.
Solution Approach 2:
Different formation methods are applied to different substrates based on their local properties. The piezoelectric substrate requires a gentle method (first through-hole formation) to avoid microcracks, while the bonded substrate can withstand a more aggressive method (second through-hole formation). This local quality approach optimizes each processing step according to the specific substrate characteristics.
2Productivity
If the same method is used to form through-holes in both substrates, then the process is simplified, but processing time increases and microcracks may occur
Solution Approach 1:
The patent applies different formation methods to different substrates based on their local properties. The piezoelectric substrate requires a gentle method (first through-hole formation) to avoid microcracks, while the bonded substrate can withstand a more aggressive method (second through-hole formation). This local quality approach optimizes each processing step according to the specific substrate characteristics, simultaneously improving productivity and reliability.
Solution Approach 2:
The patent changes the processing parameters (formation method) according to the substrate type. By varying the etching conditions, power, and other parameters between the two through-hole formation steps, the process achieves both high productivity and substrate integrity, avoiding the trade-off that would exist with a single fixed method.
3Device complexity
If a single through-hole is formed through the bonded structure, then the structure is simplified, but microcracks are generated in the piezoelectric substrate
Solution Approach 1:
The patent segments the through-hole formation into two distinct steps, each optimized for its specific substrate. This segmentation prevents microcracks in the piezoelectric substrate while maintaining relatively simple overall device structure, as the two through-holes are formed at different locations and can be connected to form a complete through-path.
Solution Approach 2:
The bonded substrate acts as an intermediary that protects the piezoelectric substrate during the second through-hole formation. By forming the first through-hole before bonding, the piezoelectric substrate is shielded from the more aggressive second formation process, allowing simplified overall structure without microcrack generation.
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 processing time, prevents microcrack generation, enhances adhesion strength, and minimizes thermal expansion-related frequency changes, leading to improved piezoelectric device performance and reliability.
Implementation Method 1
a piezoelectric substrate that is bonded to another substrate
Implementation Method 2
a formation method for the first through-hole is preferably a reactive ion etching method
Implementation Method 3
a formation method for the second through-hole is preferably a sandblast method
Data Source
AI summary
A method of manufacturing a piezoelectric device includes the steps of bonding a first substrate to a second substrate having a toughness greater than that of the first substrate, forming a first though-hole through the first substrate from the side opposite to the side on which the second substrate is bonded, and forming a second through-hole through the second substrate at a location corresponding to the first through-hole by a formation method different from that used to form the first through-hole from the side opposite to the side on which the first substrate is bonded.