Charged Polymer Polishing Composition for Glass
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Solution Overview
Problem
Conventional chemical-mechanical polishing methods are inadequate for effectively planarizing and reducing surface roughness of glass memory or rigid disks, which is crucial for improving storage capacity and shock resistance in portable devices, as they often result in reduced removal rates and increased surface roughness.
Innovation Solution
A chemical-mechanical polishing composition comprising abrasive particles, a polymer with an overall charge, and water, where the polymer encapsulates the abrasive particles, providing both steric and electrostatic barriers to prevent aggregation and improve surface finish, specifically designed for glass substrates with a pH range of 1.8 to 4.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If smaller abrasive particle size is used to decrease surface roughness, then surface roughness is reduced, but removal rate and throughput are drastically reduced
Solution Approach 1:
The patent changes the chemical parameters of the polishing composition by introducing a polymer with specific charge characteristics that interact with abrasive particles. This chemical modification allows the system to achieve both low surface roughness and high removal rate by altering the interaction mechanisms between components, rather than simply changing physical parameters like particle size
Solution Approach 2:
The patent creates a composite polishing composition by combining charged polymer molecules with abrasive particles. This composite structure allows the polymer to act as a binding agent and charge carrier, enabling the abrasive particles to work more effectively at optimized sizes without aggregation, thus achieving both precision and productivity
2Ease of manufacture
If conventional CMP methods are used for glass memory disks, then polishing can be performed, but planarity and surface finish are inadequate
Solution Approach 1:
The patent introduces a charged polymer as an intermediary substance that mediates between the abrasive particles and the glass substrate. The polymer adsorbs onto the substrate surface and facilitates controlled material removal, improving planarity while maintaining processability. The polymer acts as a chemical mediator that enhances the mechanical action of abrasives
3Productivity
If abrasive particles are used without polymer encapsulation, then removal rate is maintained, but aggregation occurs and surface finish deteriorates
Solution Approach 1:
The charged polymer serves as an intermediary that encapsulates abrasive particles, preventing their aggregation while maintaining their removal capability. The polymer coating creates steric and electrostatic barriers that keep particles dispersed, ensuring consistent surface finish without sacrificing removal rate
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 solution achieves a lower surface roughness and asperity count, enhancing the planarity and shock resistance of glass memory disks, thereby improving storage capacity and performance in portable devices.
Implementation Method 1
the polymer encapsulates the abrasive particles, providing both steric and electrostatic barriers to prevent aggregation
Implementation Method 2
the polymer encapsulates the abrasive particles, providing both steric and electrostatic barriers to prevent aggregation
Implementation Method 3
moving the polishing pad relative to the substrate with the chemical-mechanical polishing composition therebetween, and abrading at least a portion of the substrate to polish the substrate
Implementation Method 4
the abrasive particles have a zeta potential Za measured in the absence of the polymer and the abrasive particles have a zeta potential Zb measured in the presence of the polymer
Data Source
AI summary
The invention provides a chemical-mechanical polishing composition containing (a) abrasive particles, (b) a polymer, and (c) water, wherein (i) the polymer possesses an overall charge, (ii) the abrasive particles have a zeta potential Za measured in the absence of the polymer and the abrasive particles have a zeta potential Zb measured in the presence of the polymer, wherein the zeta potential Za is a numerical value that is the same sign as the overall charge of the polymer, and (iii) |zeta potential Zb|>|zeta potential Za|. The invention also provides a method of polishing a substrate with the polishing composition.