Phase-Separated Polishing Pad for Planarization and Scratch Reduction
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Solution Overview
Problem
Current polishing pads for high surface planarity, such as those used for silicon wafers, face challenges in achieving high polishing rates while minimizing scratches and maintaining planarity, especially when using hard pads.
Innovation Solution
A polishing pad with a phase-separated polyurethane resin layer formed from a curing reaction of isocyanate-terminated prepolymers derived from polyester and polyether-based polyols, combined with a chain extender, which creates a macroscopic phase-separated structure that enhances polishing rate and planarity while reducing scratching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hard polishing pads are used to increase planarity, then planarization property is improved, but scratching increases
Solution Approach 1:
The polishing pad incorporates a phase-separated structure with hard regions (providing planarity) and soft regions (providing cushioning). The polyester-based polyol forms hard domains for planarization while the polyether-based polyol forms soft domains that prevent scratching, allowing both functions to coexist in different locations within the same material.
Solution Approach 2:
The invention uses a composite polyurethane resin system combining two incompatible polymers (polyester-based and polyether-based polyols) that phase-separate during curing. This creates a microstructured composite where hard and soft phases are distributed throughout the material, enabling simultaneous achievement of high planarity and scratch resistance.
2Productivity
If polishing rate is increased, then productivity is improved, but planarity deteriorates
Solution Approach 1:
The phase-separated structure provides localized hard regions that maintain planarity even at higher polishing rates, while soft regions accommodate variations in material hardness and prevent excessive removal rates that would compromise planarity. This spatial differentiation allows aggressive polishing without sacrificing 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 phase-separated structure provides a high polishing rate and effective planarization with reduced scratching, as the island and sea components offer high overall hardness and localized low-hardness regions, optimizing the polishing process.
Implementation Method 1
a polishing layer including a product of curing reaction of a polyurethane-forming raw material composition containing: (A) an isocyanate-terminated prepolymer obtained by reaction of a prepolymer-forming raw material composition (a) containing an isocyanate component and a polyester-based polyol; (B) an isocyanate-terminated prepolymer obtained by reaction of a prepolymer-forming raw material composition (b) containing an isocyanate component and a polyether-based polyol; and a chain extender
Data Source
AI summary
An object of the invention is to provide a polishing pad which has a polishing layer with a phase-separated structure and can provide high polishing rate and high planarization property and with which scratching can be suppressed. The polishing pad comprises the polishing layer. The polishing layer comprises a product of curing reaction of a polyurethane-forming raw material composition containing: (A) an isocyanate-terminated prepolymer obtained by reaction of a prepolymer-forming raw material composition (a) containing an isocyanate component and a polyester-based polyol; (B) an isocyanate-terminated prepolymer obtained by reaction of a prepolymer-forming raw material composition (b) containing an isocyanate component and a polyether-based polyol; and a chain extender, wherein the product of curing reaction has a phase-separated structure.