Polishing Composition with End-Cationic Polymer for Wafer Defect Reduction
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Solution Overview
Problem
Current polishing compositions for semiconductor substrates, such as silicon wafers, face challenges in reducing surface defects due to limitations in controlling the chemical structure and purity of naturally-derived polymers like hydroxyethyl cellulose, while synthetic polymers offer better structural control but are difficult to match in practicality.
Innovation Solution
A polishing composition comprising a water-soluble polymer with a non-cationic main chain and a cationic region at one end, combined with silica grains as an abrasive, operating within a pH range of 8 to 12, to efficiently reduce surface defects by optimizing the interaction between the polymer and abrasive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If naturally-derived polymers like hydroxyethyl cellulose are used, then the polishing composition shows good practical performance, but the chemical structure and purity cannot be sufficiently controlled leading to surface defects
Solution Approach 1:
The invention changes the chemical structure parameters of the polymer by introducing a specific architecture: a main chain with a non-cationic region as the main structural part and a cationic region at least at one end. This structural parameter change enables better control over polymer-abrasive interactions, reducing surface defects while maintaining polishing performance
Solution Approach 2:
The invention creates a composite system by combining the specifically structured water-soluble polymer with silica grains as abrasive. The polymer composition comprises: a water-soluble polymer with a main chain formed with a non-cationic region as its main structural part and a cationic region located at least at one end of the main chain, and silica grains. This composite structure achieves both reliability and manufacturing precision
2Manufacturing precision
If synthetic polymers are used to achieve better structural control and purity, then surface defects are reduced, but the practical polishing performance is difficult to match with naturally-derived polymers
Solution Approach 1:
The invention applies local quality by creating different regions within the polymer chain: a non-cationic region as the main structural part providing structural control and purity, and a cationic region at least at one end providing the necessary interaction with abrasive particles. This local differentiation enables the polymer to simultaneously achieve surface quality and polishing performance
3Ease of manufacture
If the polymer structure is simplified for ease of manufacture, then production is easier, but the ability to reduce surface defects is compromised
Solution Approach 1:
The invention segments the polymer structure into distinct functional regions: a non-cationic region forming the main structural part of the main chain, and a cationic region located at least at one end. This segmentation allows for controlled synthesis while achieving the complex function of defect reduction, balancing ease of manufacture with surface quality
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 effectively reduces surface defects and enhances the quality of polished silicon wafers by improving the interaction between the polymer and abrasive, leading to a higher polishing rate and reduced haze.
Implementation Method 1
Such a structure allows efficient reduction of surface defects when the polymer MC-end and an abrasive having an anionic surface are present together
Data Source
AI summary
Provided is a polishing composition with which surface defects can be efficiently reduced. This invention provides a polishing composition comprising a water-soluble polymer MC-end. The main chain of the water-soluble polymer MC-end is formed with a non-cationic region as its main structural part and a cationic region located at least at one end of the main chain. The cationic region has at least one cationic group.