Colloidal Silica Composition With Low Coarse Particle Content
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Solution Overview
Problem
Existing methods struggle to effectively remove coarse particles with a particle size of 0.2 μm or more from colloidal silica, particularly when the main particles have an average size of 60 nm or more, which is challenging in chemical mechanical polishing processes for semiconductor manufacturing.
Innovation Solution
Producing colloidal silica with an average particle size of 60 to 130 nm and reducing the content of coarse particles to 10,000,000 particles/mL or less by adjusting conditions such as alkaline catalyst concentration, water content, and alcohol concentration during the hydrolysis and polycondensation of alkoxysilane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hydrolysis and polycondensation conditions are used to produce colloidal silica, then production is simpler and faster, but coarse particles with size of 0.2 μm or more cannot be effectively removed
Solution Approach 1:
The invention performs preliminary control of reaction conditions during the hydrolysis and polycondensation process to prevent coarse particle formation from the beginning. By setting specific alkaline catalyst concentration (0.1-1.0 mol/L), water content (2-10 mol per mole of alkoxysilane), and alcohol concentration (3-15 mol/L), the particle growth is controlled in advance to achieve uniform size distribution without requiring subsequent complex removal processes
Solution Approach 2:
The invention systematically changes key reaction parameters to optimize particle formation: alkaline catalyst concentration is set to 0.1-1.0 mol/L, water content to 2-10 mol per mole of alkoxysilane, and alcohol concentration to 3-15 mol/L. These parameter adjustments control the hydrolysis and polycondensation rates to produce colloidal silica with uniform particle size and minimal coarse particles
2Productivity
If submicron-sized coarse particles are added to polishing slurry to enhance polishing, then polishing rate improves, but surface roughness deteriorates
Solution Approach 1:
The invention creates a polishing slurry with differentiated particle size distribution where the majority of particles (99.99% or more) are fine particles with specific size ranges that provide smooth polishing, while eliminating coarse particles that cause roughness. The colloidal silica contains particles with Dv10 of 20-80 nm, Dv50 of 80-150 nm, and Dv90 of 150-300 nm, ensuring local quality optimization for surface finish
Solution Approach 2:
The invention creates a composite polishing slurry system combining colloidal silica with controlled particle size distribution and specific additives. The slurry contains fine silica particles in a controlled chemical environment with specific pH and additives, creating a composite material that achieves both high polishing rate and excellent surface roughness control
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 colloidal silica effectively reduces surface roughness of polished surfaces in chemical mechanical polishing processes, improving the reliability of semiconductor electrical connectivity.
Implementation Method 1
the hydrolysis and polycondensation of alkoxysilane
Implementation Method 2
the hydrolysis and polycondensation of alkoxysilane
Data Source
AI summary
A colloidal silica comprising water and silica particles, wherein the average particle size of the silica particles is 60 to 130 nm, and the content of coarse silica particles with a particle size of 0.2 μm or more among the silica particles is 10,000,000 particles/mL or less at a silica particle concentration of 1 mass.