CMP Slurry Composition for Fine-Pore Filterability and Surface Quality
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Solution Overview
Problem
Chemical-mechanical polishing compositions containing hydroxyethyl cellulose (HEC) experience reduced filterability after dilution, making it difficult to use filters with smaller pore diameters, which hinders the improvement of substrate surface quality.
Innovation Solution
The use of HEC with a low weight average molecular weight (200,000 or less) in combination with a surfactant, such as a nonionic surfactant, improves the POU filter filterability of the polishing composition even after dilution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If HEC is used in polishing composition to enhance wettability and maintain hydrophilicity, then surface quality is improved, but filterability is reduced after dilution
Solution Approach 1:
The patent changes the molecular weight parameter of HEC from conventional high values to 200,000 or less, which fundamentally alters the polymer's physical properties. This parameter change reduces viscosity and improves filterability after dilution while maintaining the wettability enhancement function on substrate surfaces.
Solution Approach 2:
The patent creates a composite system by combining low molecular weight HEC with specific additives including basic compounds (ammonia, potassium hydroxide, sodium hydroxide) and chelating agents. This composite formulation synergistically improves both surface quality and filterability, as the additives compensate for any potential loss in polishing performance from the lower molecular weight polymer.
2Reliability
If HEC is used in polishing composition, then interaction between substrate and slurry is enhanced, but POU filter filterability is reduced after dilution
Solution Approach 1:
By changing the molecular weight parameter of HEC to 200,000 or less, the patent maintains sufficient polymer-chain interaction with the substrate surface while reducing the solution's tendency to clog filters. The lower molecular weight allows better penetration and distribution in the filtration system after dilution.
Solution Approach 2:
The patent introduces basic compounds and chelating agents as intermediary substances that mediate between the HEC polymer and the filtration process. These additives modify the slurry's overall behavior, preventing filter clogging while allowing the HEC to maintain its substrate interaction function.
3Manufacturing precision
If smaller pore diameter filters are used to improve surface quality, then surface defects are reduced, but filterability of HEC-containing composition is insufficient
Solution Approach 1:
The patent's parameter change of using HEC with molecular weight of 200,000 or less directly enables the use of smaller pore diameter filters. The lower molecular weight polymer creates a less viscous, more filterable slurry that can pass through fine-pore filters without excessive clogging, thereby enabling the use of filters that can remove smaller particles and defects.
Solution Approach 2:
The patent performs preliminary filtration using the improved HEC formulation before the polishing process. By ensuring the slurry is pre-filtered through smaller pore diameter filters made possible by the low molecular weight HEC, aggregates and impurities are removed in advance, preventing surface defects during polishing.
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 approach enhances the surface quality of substrates by maintaining high POU filter filterability, allowing for effective filtration with smaller pore diameter filters, and reducing surface defects and haze.
Implementation Method 1
hydroxyethyl cellulose (HEC) is used as a water-soluble polymer for the purpose of enhancing wettability of the substrate surface in addition to an abrasive such as silica or a basic compound such as ammonia
Implementation Method 2
The use of HEC with a low weight average molecular weight (200,000 or less) in combination with a surfactant, such as a nonionic surfactant, improves the POU filter filterability of the polishing composition even after dilution
Data Source
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AI summary
The chemical-mechanical polishing composition of the present invention is for polishing a substrate and contains an abrasive, a hydroxyethyl cellulose having a weight average molecular weight of 200,000 or less, a basic component, a surfactant, and an aqueous carrier.