SAW Layered Body Bonding via Amorphous Layer Thickness Control
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Solution Overview
Problem
Layered bodies in SAW devices often have insufficient bonding strength between the piezoelectric and ceramic substrates, which affects the reliability of the devices.
Innovation Solution
A layered body is created with a ceramic substrate and a piezoelectric substrate bonded through Van der Waals force, where the ceramic substrate has a thinner amorphous layer than the piezoelectric substrate, enhancing the bonding strength by optimizing the thickness of these layers to improve flatness and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a ceramic substrate with a thick amorphous layer is used to reduce production cost, then manufacturing cost is reduced, but bonding strength between substrates deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness of the amorphous layer on the ceramic substrate and the bonding layer thickness to achieve optimal bonding strength. By adjusting these dimensional parameters within specific ranges, the invention resolves the contradiction between using cost-effective ceramic substrates and achieving sufficient bonding strength through Van der Waals force.
2Manufacturing precision
If the amorphous layer thickness is increased to improve flatness, then surface flatness is improved, but bonding strength deteriorates
Solution Approach 1:
The patent resolves this contradiction by optimizing the thickness parameters of both the amorphous layer and bonding layer. The invention specifies that the amorphous layer thickness should be 1 nm to 10 nm and the bonding layer thickness should be 1 nm to 20 nm, achieving both sufficient flatness and strong bonding strength through precise parameter control.
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 provides a SAW device with sufficient bonding strength between the substrates, enhancing the reliability and reducing production costs by using polycrystalline ceramic substrates instead of single-crystalline sapphire.
Implementation Method 1
a piezoelectric substrate formed of a piezoelectric material and having a bonding main surface that bonds to the supporting main surface through Van der Waals force
Data Source
AI summary
A layered body includes a ceramic substrate formed of a polycrystalline ceramic and having a supporting main surface and a piezoelectric substrate formed of a piezoelectric material and having a bonding main surface that bonds to the supporting main surface through Van der Waals force. The ceramic substrate includes a supporting main surface amorphous layer formed so as to include the supporting main surface. The piezoelectric substrate includes a bonding main surface amorphous layer formed so as to include the bonding main surface. The supporting main surface amorphous layer has a smaller thickness than the bonding main surface amorphous layer.