Spherical Silica Particles With Fine Voids for Plating Reliability
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Solution Overview
Problem
Existing methods for producing hollow silica particles face challenges in achieving high hollowness without compromising particle strength, and struggle to produce particles with diameters smaller than 5 μm, leading to issues in plating reliability and filler performance.
Innovation Solution
Spherical silica particles are produced using an alkaline aqueous solution of silicic acid as a raw material, involving a hydrothermal treatment and heating process to create fine voids, with specific conditions to control void size and distribution, resulting in particles with a true specific gravity retention rate of 80% or higher and a pore volume of 0.1 mL/g or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If wet template methods are used to produce hollow silica particles with large voids, then the degree of hollowness is increased, but the particle strength decreases and plating reliability is compromised
Solution Approach 1:
The patent divides the single large void into multiple fine voids distributed throughout the particle interior. This segmentation approach maintains the overall hollowness (degree of hollowness) while preventing the formation of large continuous void spaces that would compromise structural integrity. The fine voids are dispersed throughout the particle, creating a more uniform stress distribution and preventing weak points that would lead to particle fracture during via processing and plating operations.
2Length of stationary object
If conventional methods are used to produce hollow silica particles, then particles with diameters of 5 μm or smaller are difficult to obtain, but smaller particle sizes are needed for certain applications
Solution Approach 1:
The patent employs parameter changes in the sol-gel process, specifically controlling the water-to-silica molar ratio, pH conditions, and aging time to enable the formation of hollow spherical silica particles with diameters of 5 μm or smaller. By adjusting these chemical parameters during synthesis, the method achieves precise control over particle size while maintaining the hollow structure, making small particles manufacturable for the first time using this approach.
3Quantity of substance
If particles with large internal voids are used as fillers, then the degree of hollowness is high, but the voids are exposed during via processing, causing plating reliability issues
Solution Approach 1:
The patent segments the large internal voids into numerous fine voids distributed throughout the particle. This segmentation prevents the exposure of large continuous void surfaces during via processing, as the fine dispersed voids do not create the same structural weaknesses. The segmented void structure maintains high degree of hollowness while ensuring that no single void exposure would compromise plating reliability during electronic material fabrication.
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 silica particles have finer voids, enhancing their resistance to fracture under external forces and maintaining structural integrity, suitable for use as fillers in electronic materials.
Implementation Method 1
a hydrothermal treatment step of substituting, with water, a dispersion medium which is contained in the liquid dispersion and in which the raw material silica particles are dispersed, and then performing pressurization and heating to 130° C. or higher and 250° C. or lower
Implementation Method 2
a heating step of heating the liquid dispersion or the raw material silica particles obtained from the liquid dispersion through solid-liquid separation so as to remove an organic substance contained in the liquid dispersion
Implementation Method 3
a raw material silica particle preparation step of preparing a liquid dispersion of raw material silica particles from a raw material solution obtained by dissolving silicic acid in a mixed solvent of water and an organic solvent in the presence of a basic substance
Data Source
AI summary
An object is to provide a novel method for producing spherical silica particles having fine voids. That is, spherical silica particles according to the present disclosure contain silica as a main component, have an average particle diameter of 0.1 to 10.0 μm, a true specific gravity of 0.9 to 1.9 g/cm3, the true specific gravity being measured with nitrogen gas, a pore volume of 0.1 mL/g or lower, an Na content of 10 ppm or lower, and a true specific gravity retention rate of 80% or higher, the true specific gravity retention rate being measured with nitrogen gas and being a rate between before and after pressurization is performed at 300 MPa for 1 minute, and include, in an existence proportion of 60% or lower, particles in each of which a maximum value among major axes of internal voids is not smaller than half a major axis of the particle.