High-K LTCC Dielectric Compositions for Low-Temperature Sintering
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Solution Overview
Problem
Current low temperature co-fired ceramic (LTCC) systems for wireless applications face challenges in achieving high dielectric constants (K values) above 100 due to the undesirable effects of high glass content, which lowers both dielectric constant and Q factor, making it difficult to sinter materials at temperatures below 900°C.
Innovation Solution
A Barium-Titanium-Silicon-Tungstate based dielectric composition is developed, where BaCO3, TiO2, and WO3 precursors are mixed and calcined, then pulverized and mixed with fluxing agents, forming a host material that, when fired, produces a lead-free and cadmium-free dielectric material with a dielectric constant ranging from 900 to 2500, suitable for LTCC applications with noble metal metallizations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high concentration of BaO-CaO-B2O3 glass is used to enable low temperature densification, then sintering temperature is reduced to 900°C or lower, but dielectric constant K and Q factor are lowered
Solution Approach 1:
The patent changes the chemical composition parameters of the glass phase by substituting traditional BaO-CaO-B2O3 glass with a novel BaO-ZnO-B2O3-SiO2-TiO2-WO3 glass system. This compositional parameter change enables the glass to facilitate low-temperature sintering (≤900°C) while simultaneously maintaining high dielectric constant (K≥100) and acceptable Q factor, resolving the contradiction between low sintering temperature and high dielectric performance
Solution Approach 2:
The patent creates a composite ceramic system combining barium titanate (BaTiO3) ceramic phase with a specifically designed glass matrix (BaO-ZnO-B2O3-SiO2-TiO2-WO3). This composite structure allows the glass phase to act as a flux promoter for low-temperature sintering while the barium titanate phase provides the high dielectric constant, thus resolving the contradiction between low sintering temperature and high dielectric constant
2Temperature
If high concentration of BaO-CaO-B2O3 glass is used to enable low temperature densification, then sintering temperature is reduced to 900°C or lower, but Q factor is lowered
Solution Approach 1:
The patent modifies the glass composition parameters by incorporating ZnO, SiO2, TiO2, and WO3 alongside BaO and B2O3. This parameter optimization reduces dielectric losses in the glass phase while maintaining its fluxing capability at low temperatures, thereby achieving both low sintering temperature (≤900°C) and acceptable Q factor
Solution Approach 2:
The patent optimizes the local chemical environment within the glass matrix by strategically distributing different oxide components. The glass composition is designed to create specific local structures that minimize dielectric losses while maintaining low-temperature sinterability, thus resolving the contradiction between low sintering temperature and high Q factor
3Temperature
If traditional LTCC materials with K=4-8 are used, then low temperature sintering is achieved, but high dielectric constant (K>100) cannot be obtained
Solution Approach 1:
The patent develops a composite system where barium titanate ceramic particles are embedded in a specially formulated glass matrix. The barium titanate phase provides the high dielectric constant (K≥100) while the glass matrix enables low-temperature sintering (≤900°C), thus resolving the contradiction between low sintering temperature and high dielectric constant
Solution Approach 2:
The patent changes the compositional parameters of the glass phase from traditional BaO-CaO-B2O3 to a multi-component BaO-ZnO-B2O3-SiO2-TiO2-WO3 system. This parameter change allows the glass to maintain low-temperature reactivity while the barium titanate phase provides high dielectric constant, achieving both K≥100 and sintering at ≤900°C
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 achieves high dielectric constants (up to 2500) while maintaining lead and cadmium-free properties, enabling effective use in electromagnetic interference filter applications and other high-frequency components without the need for high-temperature sintering.
Implementation Method 1
calcined at about 800 to 1000° C. for about 1 to 5 hours to form a host material including BaO, TiO2, WO3 and SiO2
Implementation Method 2
Barium-Titanium-Silicon-Tungstate based dielectric compositions that exhibit a dielectric constant K=900-2500
Data Source
AI summary
Electronic devices are produced from dielectric compositions comprising a mixture of precursor materials that, upon firing, forms a dielectric material comprising a barium-titanium-tungsten-silicon oxide.