Polishing Composition Filtration for Silicon Substrate Defect Reduction
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Solution Overview
Problem
Existing polishing compositions for silicon substrates face challenges in reducing aggregates, which affect the quality of the polished product, despite the use of dispersants and polymer compounds to enhance storage stability and dispersibility.
Innovation Solution
A polishing composition is developed by filtering an undiluted liquid containing abrasive grains, a water-soluble polymer, and water, followed by dilution and further filtration of the diluted liquid to reduce foreign matters and aggregates, thereby improving the quality of the polished silicon substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dispersants and polymer compounds are added to enhance dispersibility and storage stability, then the storage stability and dispersibility of abrasive grains are improved, but aggregates still form and affect polishing quality
Solution Approach 1:
The patent applies preliminary action by filtering the polishing composition before use to remove aggregates. The filtering step is performed in advance of the polishing process, preventing aggregates from reaching the substrate and causing defects. This proactive removal of harmful particles resolves the contradiction by maintaining storage stability with dispersants while eliminating the resulting aggregates through pre-filtering.
Solution Approach 2:
The patent introduces a filter as an intermediary component between the polishing composition and the substrate. This intermediary device captures aggregates that form despite the presence of dispersants and polymers, allowing the polishing composition to maintain its stable formulation while the filter prevents harmful aggregates from affecting the polishing quality.
2Manufacturing precision
If multiple filtration steps are implemented to remove aggregates, then the quality of polished product is improved, but the process complexity increases
Solution Approach 1:
The patent segments the filtration process into two distinct steps: first filtering the polishing composition before use, and optionally a second filtration during the polishing process. This segmentation allows each filtration step to target specific types of aggregates at different stages, improving overall product quality while keeping each individual filtration step relatively simple and manageable.
3Stability of the object's composition
If abrasive grains are well-dispersed using polymer compounds, then the dispersibility is improved, but the formulation complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by optimizing the type and concentration of dispersants and polymer compounds in the formulation. By carefully selecting parameters such as polymer molecular weight, concentration ranges, and chemical composition, the patent achieves effective dispersibility while controlling formulation complexity. The filtering steps further complement this by removing aggregates that form despite optimized formulation parameters.
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 process effectively reduces foreign matters and aggregates, resulting in a high-quality polished silicon substrate with fewer light point defects and improved surface smoothness.
Implementation Method 1
filtering the undiluted liquid; diluting the filtered undiluted liquid to obtain a diluted liquid; and filtering the diluted liquid
Data Source
AI summary
A polishing composition is composed of a filtered diluted liquid obtained through an undiluted liquid-preparing step, an undiluted liquid-filtering step, a diluting step, and a diluted liquid-filtering step. In the undiluted liquid-preparing step, an undiluted liquid is prepared by mixing raw materials for the polishing composition. In the undiluted liquid-filtering step, the undiluted liquid is filtered. In the diluting step, the filtered undiluted liquid is diluted to obtain a diluted liquid. In the diluted liquid-filtering step, the diluted liquid is filtered. The polishing composition is used, for example, for polishing a silicon substrate material to produce a silicon substrate.