Polishing Composition with Modified Microfibril Cellulose
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Solution Overview
Problem
Current polishing compositions for semiconductor substrates with silica-based films face challenges in achieving high-speed polishing without causing defects like scratches and residual abrasive grains, while maintaining surface accuracy and stability.
Innovation Solution
A polishing composition comprising an abrasive grain and modified microfibril cellulose, where the cellulose units have oxidized carboxyl groups, is used to enhance friction and flowability, reducing defects and improving polishing speed through improved pressure transmissibility and scavenging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cerium oxide particles with large primary particle diameter are used, then polishing speed is improved, but polishing flaws occur due to the large particle size
Solution Approach 1:
The invention divides the cerium oxide particles into two distinct size populations: fine particles (5-50 nm) for high-speed polishing and coarse particles (0.5-5 μm) for mechanical abrasion. This segmentation allows each particle size to perform its specific function optimally without the drawbacks of using uniformly large particles throughout.
Solution Approach 2:
The invention creates a composite polishing slurry combining cerium oxide particles of different sizes with colloidal silica particles. This composite approach leverages the chemical reactivity of fine cerium oxide and the mechanical abrasion of coarse cerium oxide, while the colloidal silica provides additional polishing action and surface smoothness.
2Manufacturing precision
If colloidal silica-based polishing agents are used, then surface accuracy is improved, but polishing speed becomes slow
Solution Approach 1:
The invention changes the particle size parameter from nanoscale (5-50 nm) to microscale (0.5-5 μm) for the cerium oxide component, while maintaining the colloidal silica base. This parameter change enables significantly faster polishing speeds while preserving surface accuracy through the controlled dual-size particle mechanism.
3Productivity
If abrasive grains are used to increase polishing speed, then productivity is improved, but abrasive grain residues remain on the substrate
Solution Approach 1:
The invention introduces colloidal silica particles as intermediary substances that facilitate the removal of abrasive grain residues. The colloidal silica acts as a carrier and cleaning agent, allowing the coarse cerium oxide particles to perform mechanical abrasion while the fine colloidal silica prevents residue accumulation on the substrate 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 composition enables high-speed polishing with low defects and improved surface accuracy by effectively trapping abrasive grains and reducing residual contamination, thus enhancing the stability and efficiency of the polishing process.
Implementation Method 1
modified microfibril cellulose, which enhances mechanical friction and flowability
Implementation Method 2
includes specific acid and base components to stabilize pH and ionic strength
Data Source
AI summary
A polishing composition comprising an abrasive grain; a modified microfibril cellulose in which at least a part of the cellulose units has a hydroxyl group at the C6 position oxidized to a carboxyl group; and a dispersion medium, wherein each content of Na and K is 100 ppm or less relative to the solids weight.