Spherical Forsterite Particles for Low Dielectric Loss Resin Compositions
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Solution Overview
Problem
Current resin compositions for printed circuit boards suffer from high dielectric loss at high frequencies due to the use of non-spherical, lumpy forsterite particles, which reduce the insulating properties and increase signal transmission loss.
Innovation Solution
Production of spherical forsterite particles with a low dielectric loss tangent by controlling the MgO/SiO2 molar ratio and surface treatment with hydrolyzable silanes, followed by thermal spraying and re-firing to achieve specific particle size, sphericity, and crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-spherical forsterite particles are used as filler in resin compositions, then the insulating property is improved, but the dielectric loss increases at high frequencies
Solution Approach 1:
The patent applies spheroidality by transforming angular forsterite particles into spherical particles through thermal spraying. This shape transformation reduces the dielectric loss tangent from 0.003-0.005 (angular particles) to 0.0015 or less (spherical particles), while maintaining the low relative permittivity of forsterite. The spherical shape improves high-frequency characteristics by reducing polarization reversal losses.
Solution Approach 2:
The patent changes physical parameters including particle shape (from angular to spherical), particle size (controlling average diameter), and surface properties (through hydrolyzable silane coating). These parameter changes optimize the balance between insulating properties and dielectric loss, achieving low dielectric loss tangent while maintaining high insulation performance.
2Reliability
If forsterite particles are used to reduce dielectric loss, then high-frequency characteristics improve, but the particle shape becomes lumpy or angular reducing toughness
Solution Approach 1:
The patent transforms angular forsterite particles into spherical particles with a sphericity of 0.95 or more. This spherical shape is achieved through thermal spraying which melts and respheroidizes the particles. The spherical morphology improves both the high-frequency dielectric characteristics and the toughness of the composite insulating material by eliminating stress concentration points associated with angular shapes.
3Ease of manufacture
If forsterite particles are spheroidized to improve blending with resin, then ease of manufacture improves, but additional processing steps are required
Solution Approach 1:
The patent employs thermal spraying to spheroidize forsterite particles, which significantly improves their blendability with resin matrices. The spherical particles distribute more uniformly and create fewer voids compared to angular particles. Although thermal spraying adds a processing step, it enables direct production of spherical particles without requiring subsequent mechanical grinding or classification, simplifying the overall manufacturing workflow.
Solution Approach 2:
The patent controls particle size parameters (average diameter and size distribution) through the thermal spraying process to optimize blending characteristics. By adjusting spray parameters, the particles are produced with sizes and distributions that facilitate easy mixing with resin, reducing the need for additional size classification steps.
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 spherical forsterite particles exhibit improved high-frequency characteristics with reduced dielectric loss, enhanced insulating properties, and ease of blending with resins, leading to better signal transmission and substrate material performance.
Implementation Method 1
putting forsterite particles into a hydrocarbon combustion flame
Implementation Method 2
firing the forsterite particles obtained in step (B) at 700° C. to 1,100° C.
Data Source
AI summary
Forsterite particles have an average size of 0.1 μm to 10 μm and a dielectric loss tangent of 0.0003 to 0.0025. Sphericity=(Average particle size (μm) measured with a laser diffraction particle size distribution analyzer)/(Average primary particle size (μm) calculated by conversion using specific surface area measured by a nitrogen gas adsorption method) may be from 1.0 to 3.3. This method for producing forsterite particles may include: step (A): mixing a magnesium compound as a magnesium source and a silicon compound as a silicon source so MgO/SiO2 has a molar ratio of 1.90 to 2.10 to prepare particles; step (B): putting the particles prepared in step (A) into a hydrocarbon combustion flame to recover the resulting particles; and step (C): firing the particles obtained in step (B) at 700° C. to 1100° C. The ratio between a resin and the particles may be 1:0.001 to 1000 by mass ratio.