Silica Particle Dispersion via Fine Bubble Hydrolysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for producing high-purity silica sols face challenges such as contamination from nitrogen-containing compounds, difficulty in achieving monodispersed particles of 10 nm or less, and reproducibility issues due to the use of alkaline catalysts, which can lead to defects in semiconductor wafer production and reduced yield.
Innovation Solution
The production of high-purity silica particles is achieved by hydrolyzing silane alkoxide in the presence of fine bubbles with an average diameter of 40 nm to 10 μm, eliminating the need for alkaline catalysts and resulting in particles with an average size of 3 to 10 nm, thereby minimizing contamination and improving particle uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If alkaline catalysts (ammonia or amine compounds) are used for hydrolysis and pH adjustment, then the hydrolysis reaction rate is improved, but nitrogen-containing compound contamination occurs leading to wafer defects and reduced yield
Solution Approach 1:
The invention extracts and removes the harmful alkaline catalyst (ammonia or amine compound) from the hydrolysis process. Instead of using traditional alkaline catalysts, the patent employs a controlled hydrolysis method that proceeds without nitrogen-containing catalysts, thereby eliminating the source of contamination while still achieving effective hydrolysis of silane alkoxide to produce silica particles
Solution Approach 2:
The invention replaces the reusable but contaminating alkaline catalyst system with a disposable alternative approach. The hydrolysis is conducted using carefully controlled conditions with water and acid/base adjustment after reaction, rather than relying on persistent alkaline catalysts. This allows the process to achieve high reaction rates temporarily without long-term contamination risks
2Manufacturing precision
If reaction rate is adjusted to obtain fine particles, then small particle size silica sol is produced, but microgel is generated by reaction between produced particles and non-hydrolyzate making it difficult to obtain monodispersed particles
Solution Approach 1:
The invention applies preliminary action by carefully controlling the hydrolysis conditions from the very beginning of the reaction. The patent uses controlled addition of water to silane alkoxide under specific temperature and stirring conditions to ensure uniform hydrolysis rates. This preliminary control prevents local excesses of non-hydrolyzate that would otherwise lead to microgel formation, enabling monodispersed particle production
Solution Approach 2:
The invention employs parameter changes by systematically adjusting reaction conditions including temperature, water addition rate, stirring speed, and pH control during hydrolysis. These parameter optimizations ensure that hydrolysis proceeds at a rate that maintains uniform particle growth without generating microgels, achieving both fine particle size and monodispersity
3Quantity of substance
If alkaline catalyst is used to generate fine seeds during hydrolysis, then particle formation is initiated, but a large amount of alkali is required causing particles to grow to size greater than 10 nm
Solution Approach 1:
The invention applies partial action by using minimal water addition in the initial stage to generate just enough nuclei without excessive growth. The patent controls the water-to-silane ratio and addition rate to produce a sufficient number of seed particles while preventing over-growth. This partial hydrolysis approach creates numerous small nuclei that remain below 10 nm in size, avoiding the need for large amounts of alkali that would promote excessive particle growth
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
This method produces silica particles with high purity and uniform size distribution, reducing the risk of contamination and defects in semiconductor production, and eliminates the need for solvent substitution, leading to lower manufacturing costs and improved filterability.
Implementation Method 1
hydrolyzing silane alkoxide in a liquid phase containing fine bubbles having an average bubble diameter of 40 nm to 10 μm
Implementation Method 2
fine bubbles (micro-nano bubbles) having an average bubble diameter of 40 nm to 10 μm
Data Source
AI summary
Provided is a dispersion containing high-purity silica particles and a method for producing the same. A first solution containing a silane alkoxide and a second solution containing fine bubbles having an average bubble diameter of 40 nm to 10 μm are mixed. Thus, the silane alkoxide is hydrolyzed without using an alkaline catalyst in a liquid phase containing the fine bubbles, so that uniform silica particles having an average particle size of 3 to 10 nm are produced. Further, hydrolysis is carried out by adding a hydrolyzable metal compound to the dispersion containing the silica particles in the presence of the fine bubbles and the alkaline catalyst. Thus, the silica particles are grown, so that a uniform silica-based particle dispersion containing particles having an average particle size of more than 10 nm and 300 nm or less is produced.