Zirconia Slurry pH Control for Scratches
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Solution Overview
Problem
Current polishing compositions for semiconductor substrates contain an insufficient number of coarse particles, leading to scratches and residues during the polishing process, as existing methods fail to adequately reduce the number of coarse particles.
Innovation Solution
A method for producing an inorganic particle-containing slurry by preparing an inorganic particle dispersion with a pH less than the isoelectric point of the particles and adding an alkaline compound to prevent particle aggregation, thereby reducing the number of coarse particles and minimizing defects during polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing compositions are used, then polishing can be performed on semiconductor substrates, but coarse particles are not sufficiently reduced leading to scratches and residues
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pH of the slurry to be within 0.1-2.0 units below the isoelectric point of zirconia particles, and controlling the particle size distribution with D50 of 0.03-0.10 μm and D90 of 0.06-0.20 μm. These parameter optimizations prevent particle aggregation and reduce coarse particles, thereby improving polishing surface quality while minimizing scratches and residues
Solution Approach 2:
The patent implements preliminary action by pre-adjusting the pH of the slurry before polishing to ensure it is within the optimal range below the isoelectric point. This preliminary pH adjustment prevents particle aggregation during storage and application, ensuring that the slurry maintains a fine particle size distribution and does not generate coarse particles that would cause defects on the polished surface
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 method effectively reduces the number of coarse particles in the slurry, resulting in fewer scratches and residues on the polished surface, enhancing the polishing process's efficiency and quality.
Implementation Method 1
adding an alkaline compound to the inorganic particle dispersion in such a manner that the pH does not reach the isoelectric point of the inorganic particles
Implementation Method 2
preparing an inorganic particle dispersion containing inorganic particles and a dispersing medium, and having a pH less than the isoelectric point of the inorganic particles
Data Source
AI summary
The present invention provides a method for producing an inorganic particle-containing slurry, by which the number of coarse particles can be sufficiently reduced. The present invention is a method for producing an inorganic particle-containing slurry, which comprises: a step of preparing an inorganic particle dispersion containing inorganic particles and a dispersing medium, and having a pH less than the isoelectric point of the inorganic particles; and a step of adding an alkaline compound to the inorganic particle dispersion in such a manner that the pH does not reach the isoelectric point of the inorganic particles.