Silica Spherical Particles for Semiconductor Sealing
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Solution Overview
Problem
Existing silica spherical particles struggle to achieve both high fluidity and effective filling in narrow gaps for semiconductor sealing and heat dissipation applications, often resulting in voids or impaired thermal conductivity due to limitations in particle diameter and roundness.
Innovation Solution
Silica spherical particles with specific diameter and roundness characteristics, including D99≤29 μm, 10 μm≤Dmode<D99, D99/Dmode≤1.5, and Dmode≤20 μm, along with high roundness and controlled Rosin-Rammler distribution, are developed to enhance fluidity and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the particle diameter of spherical silica is reduced to achieve underfill in narrow gaps, then the filling capability is improved, but the fluidity deteriorates and voids form in the package
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle diameter distribution (D99≤29 μm, Dmode≤20 μm) and roundness (0.7 or more) of spherical silica particles to achieve optimal balance between filling capability and fluidity. This parameter optimization allows the sealing material to fill narrow gaps effectively while maintaining sufficient fluidity to avoid void formation.
Solution Approach 2:
The patent utilizes spheroidality by employing spherical silica particles with high roundness (0.7 or more). The spherical shape enables better flow characteristics and fluidity compared to angular particles, while still providing effective filling in narrow gaps. The spherical geometry reduces particle interlocking and improves mobility within the sealing material.
2Manufacturing precision
If the particle diameter is reduced to fill narrow gaps, then the filling property is improved, but the thermal conductivity deteriorates due to reduced thermal pathways
Solution Approach 1:
The patent resolves this contradiction by optimizing the particle size distribution parameters (D99≤29 μm, Dmode≤20 μm) to achieve the smallest effective particle diameter for filling while maintaining sufficient thermal conductivity. The controlled particle size ensures adequate thermal pathways remain intact even at reduced dimensions.
3Manufacturing precision
If separate sealing and overfill operations are performed with different resins, then the sealing quality is improved, but the productivity and cost are greatly compromised
Solution Approach 1:
The patent applies universality by developing a single sealing material composition that can perform both sealing and overfill functions. The material contains spherical silica particles with specific characteristics (D99≤29 μm, high roundness) that enable it to fill narrow gaps effectively while maintaining fluidity for overfill applications. This multi-functional capability eliminates the need for separate operations with different resins, thereby improving productivity and reducing cost.
4Volume of moving object
If the gap between silicon chip and substrate is narrowed, then the space saving is improved, but the sealing difficulty increases due to narrow gap requirements
Solution Approach 1:
The patent resolves this contradiction by optimizing the particle size parameters (D99≤29 μm, Dmode≤20 μm) to ensure the sealing material can effectively fill progressively narrower gaps. The controlled particle size distribution enables the material to adapt to decreasing gap dimensions while maintaining proper filling capability and fluidity.
Data Source
AI summary
The purpose of the present invention is to provide: silica particles of which the maximum particle diameter can be minimized and which can achieve proper fluidability that cannot be achieved by the conventional techniques; and silica spherical particles which, when used as a filler for a heat-dissipating sheet, can achieve excellent heat conductivity and flexibility. Silica spherical particles characterized in that, when particles each having a size of 5 μm or more and imaged by an optical measurement are observed, the particle diameter of each of the particles, which is determined from the image, satisfies the following requirements. Requirements: D99≤29 μm, and 10 μm≤Dmode<D99, and D99/Dmode≤1.5, and Dmode≤20 μm.