LTCC Dielectric Composition With Tunable Permittivity and Low-Temp Co-Firing
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Solution Overview
Problem
Current low temperature co-fired ceramic (LTCC) materials have fixed dielectric constants, which limits their application in integrated modules where adjustable dielectric constants are needed. Additionally, the high-temperature melt-quenching method used to prepare glass in these materials leads to volatilization of volatile components, affecting the final product's composition and performance.
Innovation Solution
A low temperature co-fired dielectric material with an adjustable dielectric constant is developed, comprising a zirconia main phase and a silicon-based amorphous filler. The weight ratio of zirconia to silicon-based amorphous filler is 40-65:35-60, with a SiO2 weight percentage of ≥50%. This material system allows for dielectric constant adjustment between 7 and 12, reducing dielectric loss and avoiding defects like laminar cracks and warping during co-firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If glass is prepared by melt-quenching method to reduce sintering temperature, then sintering temperature is reduced, but volatile components evaporate causing composition deviation and performance degradation
Solution Approach 1:
The patent changes the preparation method parameters from high-temperature melt-quenching to low-temperature sol-gel process, enabling glass powder formation at temperatures below 1000°C. This parameter change prevents volatile component evaporation while achieving the desired glass composition and sintering temperature reduction.
Solution Approach 2:
The patent replaces the thermal-mechanical melt-quenching process with a chemical sol-gel process. Instead of melting and quenching glass at high temperatures, metal alkoxides undergo hydrolysis and condensation reactions to form glass powder in situ, substituting thermal processing with chemical processing.
2Reliability
If zirconia is used as a nucleating agent in glass-ceramic system with fixed composition ratio, then material performance is optimized, but dielectric constant becomes fixed and cannot be adjusted
Solution Approach 1:
The patent introduces dynamic adjustability to the dielectric constant by varying the zirconia content within a range (1-10 wt%) rather than using a fixed composition. This allows the dielectric constant to be tuned dynamically according to application requirements while maintaining optimal material performance through controlled crystallization.
Solution Approach 2:
The patent creates a composite glass-ceramic system combining glass matrix with zirconia crystalline phases. This composite structure enables both optimized material performance through controlled crystallization and adjustable dielectric constant by varying the zirconia content and distribution within the glass matrix.
3Adaptability or versatility
If different materials with different dielectric constants are used in integrated module, then functional requirements are met, but laminar cracks and warping occur during co-firing
Solution Approach 1:
The patent creates a universal glass-ceramic base material system that can accommodate different functional requirements by adjusting zirconia content. This multi-functional material can serve different dielectric constant requirements within a single material system, eliminating the need for multiple different material systems and their associated co-firing compatibility issues.
Solution Approach 2:
The patent achieves homogeneous sintering characteristics within the glass-ceramic system by maintaining a consistent glass matrix composition while varying only the zirconia content. This homogeneity in the base material system ensures uniform thermal expansion and sintering behavior, preventing laminar cracks and warping during co-firing while still allowing dielectric constant adjustment.
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 material achieves a tunable dielectric constant within a wide range of 7-12, with low dielectric loss of 0.1% at 1 MHz, and can be co-fired with a silver electrode without defects, making it suitable for use in LTCC materials.
Implementation Method 1
the glass is mainly used to reduce the sintering temperature
Implementation Method 2
zirconia is used as a nucleating agent to control the crystallization of glass
Data Source
AI summary
Disclosed is a low temperature co-fired dielectric material with an adjustable dielectric constant, wherein it comprises a zirconia main phase and a silicon-based amorphous filler, a weight ratio of the zirconia main phase to the silicon-based amorphous filler is 40-65:35-60; a weight percentage of SiO2 in the silicon-based amorphous filler is ≥50%. The dielectric constant of low temperature co-fired dielectric material can be continuously adjusted in a wide range of 7-12, the dielectric loss can be as low as 0.1% at 1 MHz. The material system can be sintered at 800-900° C. and co-fired with silver electrode. It can be used as the low temperature co-fired dielectric material. The invention also discloses a method for preparing the low temperature co-fired dielectric material with an adjustable dielectric constant.