Glass-Ceramic Composition for Low Dielectric Loss and Boron Stability
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Solution Overview
Problem
Glass-ceramic materials with high boron content for low-temperature fired boards face issues of boron elution and volatilization, leading to unstable viscosity, insufficient sintering, low moisture resistance, and plating solution resistance, as well as a mismatch in thermal expansion coefficients with other dielectrics, causing quality failures.
Innovation Solution
A glass-ceramic composition containing Si, B, Al, and Zn, with specific weight ratios of SiO2, B2O3, Al2O3, and ZnO, and the presence of crystal phases like SiO2, ZnAl2O4, and Al2O3, which stabilizes boron content, enhances sintering, and adjusts thermal expansion coefficients, resulting in a low relative dielectric constant, low dielectric loss, and high thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high boron content glass composition is used for low-temperature firing, then dielectric loss is reduced, but boron content becomes unstable due to elution and volatilization
Solution Approach 1:
The patent changes the chemical composition parameters by adding ZnO (5-20 wt%) and controlling SiO2 (60-75 wt%), B2O3 (10-25 wt%), and Al2O3 (5-15 wt%) ratios. This parameter adjustment allows the glass to maintain low dielectric loss while improving boron stability through the formation of ZnAl2O4 spinel crystals that trap boron and prevent its elution and volatilization during firing and processing.
Solution Approach 2:
The patent creates a composite glass-ceramic system combining glass matrix with ZnAl2O4 spinel crystals and SiO2 aggregates. This composite structure allows the glass phase to provide low dielectric loss while the crystalline phases stabilize boron content by incorporating it into their structures, preventing boron loss during processing.
2Loss of energy
If high boron content glass is used, then dielectric loss decreases, but viscosity becomes insufficient during firing due to boron loss
Solution Approach 1:
The patent adjusts composition parameters to include ZnO (5-20 wt%) and controls the SiO2/B2O3 ratio between 2.4-7.5. This parameter change ensures adequate viscosity during firing by forming ZnAl2O4 crystals that maintain structural integrity even when boron content varies, preventing insufficient sintering while preserving low dielectric loss.
Solution Approach 2:
The ZnO and Al2O3 components act as intermediaries that stabilize the glass structure during firing. They form ZnAl2O4 spinel crystals that serve as a buffer, maintaining viscosity and sintering quality even when boron is lost through elution or volatilization, thus mediating between the conflicting requirements of low dielectric loss and adequate sintering.
3Strength
If glass with decreased boron content is used, then sintering improves, but chemical stability and moisture resistance deteriorate
Solution Approach 1:
The patent employs a composite glass-ceramic structure where the glass matrix provides chemical stability and moisture resistance, while the ZnAl2O4 spinel crystals and SiO2 aggregates provide structural stability during sintering. This composite approach allows the system to achieve good sintering quality without sacrificing chemical stability, as the crystalline phases protect the glass matrix from degradation.
Solution Approach 2:
The patent modifies composition parameters by adding ZnO (5-20 wt%) and controlling the ratios of SiO2, B2O3, and Al2O3. This parameter adjustment creates a balanced composition where ZnO and Al2O3 work together to improve sintering quality through ZnAl2O4 crystal formation while simultaneously enhancing chemical stability and moisture resistance by forming a protective crystalline network.
4Loss of energy
If low coefficient of thermal expansion glass-ceramic is used, then dielectric loss is low, but thermal expansion mismatch with mounting boards causes quality failure
Solution Approach 1:
The patent changes the thermal expansion parameter by adding ZnO (5-20 wt%) and controlling the composition ratios. This parameter modification increases the coefficient of thermal expansion to 6-11 ppm/K, improving compatibility with mounting boards and other dielectrics while maintaining low dielectric loss through the optimized glass-ceramic composition and ZnAl2O4 crystal formation.
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 glass-ceramic with improved sinterability, chemical stability, and thermal expansion matching, achieving a low relative dielectric constant, low dielectric loss, and high flexural strength, suitable for electronic components, especially in the millimeter wave band.
Implementation Method 1
Glass-ceramic materials that can be fired at low temperatures are known as ceramic materials for ceramic multilayer wiring boards
Implementation Method 2
the glass ceramic comprises crystal phases of SiO2, ZnAl2O4, and Al2O3
Data Source
AI summary
A glass-ceramic containing: glass containing Si, B, Al, and Zn; crystal phases of SiO2, ZnAl2O4, and Al2O3; and an aggregate, wherein, with respect to a weight of the glass-ceramic, a content of the glass is 45% by weight to 80% by weight and, as the aggregate, a content of SiO2 is 20% by weight to 50% by weight, a content of Al2O3 is 20% by weight or less, and a content of ZnO is 10% by weight or less.