Oxide Composite Particles Core-Shell Structure for Low Dielectric Resin
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Solution Overview
Problem
Oxide composite particles containing crystalline silica, such as quartz and cristobalite, are difficult to maintain a spherical shape, which is desirable for achieving low dielectric constant and low dielectric loss tangent in resin compositions for high-frequency devices.
Innovation Solution
The development of oxide composite particles with a specific composition and production method, including a mixture of silica and aluminum oxide phases, heated to form a core-shell structure with a high aluminum-to-silicon ratio, maintaining high sphericity and achieving low dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crystalline silica (quartz, cristobalite) is used to improve thermal conductivity, then heat dissipation properties are improved, but spherical shape is lost and dielectric properties deteriorate
Solution Approach 1:
The invention applies local quality by creating a core-shell structure where the core contains crystalline silica phases (cristobalite, quartz) for thermal conductivity, while the shell contains amorphous silica and aluminum oxide for maintaining spherical shape and providing low dielectric properties. This localized differentiation allows each region to fulfill its specific function without compromising the overall particle morphology or dielectric performance.
Solution Approach 2:
The invention uses composite materials by combining multiple silica phases (amorphous silica, cristobalite, quartz) with aluminum oxide in a core-shell configuration. The core comprises crystalline silica for thermal conductivity, while the shell comprises amorphous silica and aluminum oxide for shape maintenance and dielectric properties, creating a multi-phase composite that simultaneously achieves thermal and electrical performance.
2Temperature
If amorphous spherical silica is crystallized to improve thermal conductivity, then heat dissipation is improved, but dielectric constant and loss tangent increase
Solution Approach 1:
The invention applies local quality by restricting crystallization to the core region only, while maintaining amorphous structure in the shell. The core contains crystalline phases (cristobalite, quartz) that provide thermal conductivity, while the shell maintains amorphous silica structure that preserves low dielectric constant and loss tangent, thus locally optimizing for thermal properties without compromising electrical performance.
Solution Approach 2:
The invention uses composite materials by combining crystalline silica phases (cristobalite, quartz) in the core with amorphous silica and aluminum oxide in the shell. This multi-phase composite structure allows the crystalline core to provide thermal conductivity while the amorphous shell maintains excellent dielectric properties, achieving a balance between thermal and electrical performance that cannot be obtained by complete crystallization.
3Shape
If aluminum oxide coating is applied to maintain spherical shape, then shape is improved, but dielectric properties deteriorate
Solution Approach 1:
The invention applies local quality by limiting aluminum oxide to the shell region where it serves to maintain spherical shape and prevent aggregation, while the core contains crystalline silica phases for thermal conductivity. The aluminum oxide in the shell provides structural integrity and shape maintenance without significantly impacting the overall dielectric properties, as the core crystalline phases dominate the thermal performance while the shell provides morphological stability.
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 resulting oxide composite particles provide a resin composition with low dielectric constant and low dielectric loss tangent, enhancing heat dissipation and moldability for high-frequency substrates.
Implementation Method 1
heating the mixture at 1300 to 1700° C. for 2 to 8 hours
Implementation Method 2
the oxide composite particles contain 10 to 90% by mass of an α-cristobalite crystal phase, 50% by mass or less of an α-alumina crystal phase, and more than 10% by mass of a mullite crystal phase
Data Source
AI summary
Provided are oxide composite particles closer to a sphere that are mixed with a resin to obtain a resin composition having low dielectric constant and low dielectric loss tangent. The oxide composite particles containing silica and an oxide of aluminum (a single oxide or a composite oxide, or both), in which the oxide composite particles contain 10 to 90% by mass of an α-cristobalite crystal phase, 50% by mass or less of an α-alumina crystal phase, and more than 10% by mass of a mullite crystal phase, and an elemental ratio of aluminum to silicon (aluminum/silicon) as determined by X-ray photoelectron spectroscopy is 0.1 or more.