Silica Sol for Semiconductor Resins
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Solution Overview
Problem
Nano-size silica particles used in semiconductor applications face challenges due to high moisture absorption and α-ray emission rates, which impair insulation performance and mechanical strength, and existing solutions struggle to achieve low moisture absorption and low α-ray emission simultaneously.
Innovation Solution
A silica sol containing nano-size silica particles with a mean primary particle size of 20 to 100 nm, surface-treated with 0.1 to 5 molecules of an organic silane compound per nm², and produced from high-purity active silicic acid through cation and anion exchange, resulting in a low α-ray emission rate and moisture absorption coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If nano-size silica particles are used to reduce linear expansion coefficient, then the linear expansion coefficient is reduced, but the moisture absorption increases
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution ratio (PSD) to achieve optimal performance. Specifically, it defines the ratio of D10 to D90 particle sizes and controls the content of particles with D10/D90 ≤ 1.2 to be 5-50 wt%, which optimizes both linear expansion coefficient reduction and moisture absorption control
Solution Approach 2:
The patent creates a composite silica particle system combining particles with different size distributions and surface properties. It uses composite materials including silica particles with specific surface area (100-500 m²/g) and controlled pore structures to achieve both low linear expansion coefficient and low moisture absorption simultaneously
2Length of moving object
If high charging ratio of silica filler is used to reduce linear expansion coefficient, then the linear expansion coefficient is reduced, but the flowability deteriorates
Solution Approach 1:
The patent segments the silica particle size distribution into multiple ranges: D10/D90 ≤ 1.2 particles (5-50 wt%), 1.2 < D10/D90 ≤ 2.0 particles (20-70 wt%), and D10/D90 > 2.0 particles (5-30 wt%). This segmentation allows optimization of flowability through controlled particle size distribution while maintaining high charging ratio for linear expansion coefficient reduction
Solution Approach 2:
The patent applies local quality by controlling the surface properties of specific particle size ranges. It treats particles with D10/D90 ≤ 1.2 to have specific surface area (100-500 m²/g) and controlled pore structures, which locally optimizes both flowability and functional performance
3Ease of manufacture
If silica sol produced from sodium silicate is used, then the production cost is reduced, but the α-ray emission rate increases
Solution Approach 1:
The patent extracts and removes harmful radioactive elements from the silica sol production process. It specifies that the silica sol must have α-ray emission rate of 0.005 counts/cm²/s or less, which requires using high-purity raw materials and purification processes to extract uranium and thorium contaminants
Solution Approach 2:
The patent changes the purity parameter of the silica sol by specifying α-ray emission rate ≤ 0.005 counts/cm²/s and using raw materials with controlled radioactive content. This parameter change ensures low radiation while maintaining production feasibility through regulated material selection
4Reliability
If surface-hydrophobicized silica powder is used to reduce moisture absorption, then the moisture absorption is reduced, but the compatibility with resin deteriorates
Solution Approach 1:
The patent applies local quality by controlling surface properties of specific particle size ranges. It specifies that particles with D10/D90 ≤ 1.2 should have surface area (100-500 m²/g) and controlled pore structures, creating local variations in surface chemistry that balance hydrophobicity with resin compatibility
Solution Approach 2:
The patent changes surface chemistry parameters by controlling surface area (100-500 m²/g) and pore structure characteristics. These parameter changes optimize the balance between moisture absorption resistance and resin compatibility through controlled surface properties
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 silica sol achieves a low α-ray emission rate and moisture absorption coefficient, enabling the production of resin products with improved insulation performance and mechanical strength for semiconductor applications.
Implementation Method 1
surface-treated with 0.1 to 5 molecules of an organic silane compound per nm²
Implementation Method 2
surface-treated with 0.1 to 5 molecules of an organic silane compound per nm²
Implementation Method 3
produced from high-purity active silicic acid through cation and anion exchange
Implementation Method 4
silica particles having a mean primary particle size of 20 to 100 nm
Data Source
AI summary
A silica sol having a silica particle size/average primary particle size ratio measured by dynamic light scattering of 3.0 or lower, the silica sol containing silica particles having an average primary particle size of 20-100 nm surface modified by an organic silane compound having α-ray emission of 0.005 count/cm2·hr or less and a coefficient of moisture absorption of 0.5 mass% or less when allowed to stand for 48 hours in a 23°C, 50% relative humidity (RH) environment.