Glass-Ceramic Laminate with Boron Gradient for Low-Loss Strength
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Solution Overview
Problem
Existing laminates for electronic components face challenges in achieving low permittivity, high mechanical strength, and high Q value simultaneously, with previous solutions either compromising on mechanical strength due to high SiO2 filler content or reducing Q value by replacing quartz with glass or amorphous SiO2.
Innovation Solution
A laminate composed of multiple glass ceramic layers with quartz and a glass containing SiO2, B2O3, Al2O3, and an alkali metal oxide, where the boron concentration is lower in the surface layer than the inner layer, produced by stacking glass ceramic green sheets and firing in a steam environment, maintains low permittivity and high mechanical strength while preventing a decrease in Q value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a dielectric material containing a large amount of SiO2 filler is used to lower permittivity, then the permittivity of the insulating portion is reduced, but the mechanical strength becomes low
Solution Approach 1:
The patent applies local quality by creating a gradient in boron concentration across the laminate thickness. The surface layer portion has a lower B concentration (0.1-2.0 mass%) while the inner layer portion has a higher B concentration (2.1-4.0 mass%). This spatial variation in composition allows the surface layer to achieve low permittivity (similar to SiO2-rich materials) while the inner layer provides mechanical strength support, resolving the contradiction between low permittivity and high mechanical strength.
2Stability of the object's composition
If quartz is replaced by glass or amorphous SiO2 to achieve lower coefficient of thermal expansion in the surface layer, then the coefficient of thermal expansion is reduced, but the Q value becomes low
Solution Approach 1:
The patent uses parameter changes by precisely controlling the boron concentration parameter in the glass composition. By maintaining B concentration within specific ranges (0.1-2.0 mass% in surface layer, 2.1-4.0 mass% in inner layer) and combining with specific SiO2, Al2O3, and other oxide contents, the patent achieves the desired coefficient of thermal expansion while preserving high Q value. This is accomplished without replacing quartz with amorphous materials, thus avoiding the Q value degradation that would otherwise occur.
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 laminate achieves a relative permittivity of 4.5 or lower, a Q value of 450 or higher, and flexural strength of 200 MPa or more, ensuring high reliability and mechanical integrity for electronic components.
Implementation Method 1
the laminate achieves a relative permittivity of 4.5 or lower, a Q value of 450 or higher
Implementation Method 2
firing the multilayer green sheet to provide a glass ceramic layer, wherein the firing is performed in an environment containing steam
Data Source
AI summary
The laminate of the present disclosure includes multiple glass ceramic layers each containing quartz and a glass that contains SiO2, B2O3, Al2O3, and M2O, where M is an alkali metal. The B concentration of a surface layer portion of the laminate is lower than the B concentration of an inner layer portion of the laminate.