Polyurethane Polishing Pad Pore Communication
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Solution Overview
Problem
Polishing pads used in semiconductor and glass substrate polishing face challenges with hydrophobicity leading to poor affinity for polishing liquids, clogging, and reduced flatness due to inadequate communication between pores, affecting polishing performance and product quality.
Innovation Solution
A polishing pad with a resin foamed body formed by a dry molding method, featuring communication holes between adjacent pores at a ratio of 800 holes/cm² or more, enhancing liquid affinity and retention properties, and a manufacturing method involving a polyurethane composition with a silicone-based surfactant to optimize pore structure and water absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polyurethane foamed body is formed by a dry molding method, then the structure is simple and manufacturing is easier, but the polishing liquid affinity is poor due to hydrophobicity
Solution Approach 1:
The invention changes the chemical composition parameters of the polyurethane foam by incorporating hydrophilic compounds (polyethylene glycol, polypropylene glycol) into the polymer structure. This modifies the hydrophobicity parameter of the base material, enabling it to affinity polishing liquid while maintaining the dry molding manufacturing method.
Solution Approach 2:
The invention creates a composite material system by combining hydrophobic polyurethane base material with hydrophilic additives (polyethylene glycol, polypropylene glycol). This composite structure integrates the mechanical properties of polyurethane with the liquid affinity properties of the hydrophilic compounds, resolving the contradiction between ease of manufacture and polishing liquid affinity.
2Reliability
If the number of opened pores or grooves is increased to improve supplying and retaining properties to polishing liquid, then liquid retention improves, but elasticity is lost and flatness deteriorates
Solution Approach 1:
The invention changes the chemical composition parameter of the polyurethane material by adding hydrophilic compounds, which improves polishing liquid retention through enhanced affinity without requiring an increase in pore number or groove density. This maintains the structural integrity and elasticity needed for flatness.
3Reliability
If pores are formed continuously in the resin foamed body, then polishing liquid cycling and retaining properties are secured, but elastic fatigue occurs when used repeatedly
Solution Approach 1:
The invention uses a composite material system combining polyurethane with hydrophilic compounds (polyethylene glycol, polypropylene glycol). This composite structure provides both the continuous pore architecture needed for polishing liquid cycling and enhanced elasticity that resists fatigue, extending service life while maintaining cycling properties.
4Productivity
If opened pores are formed at the polishing surface, then polishing liquid supply and discharge properties improve, but clogging occurs due to poor affinity
Solution Approach 1:
The invention changes the surface chemical composition parameter by incorporating hydrophilic compounds into the polyurethane matrix. This modifies the surface energy and wetting properties, enabling polishing liquid to affinity the opened pores effectively, preventing clogging while maintaining supply properties.
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 improves the polishing pad's affinity to polishing liquids, stabilizes polishing performance, and maintains flatness by ensuring effective liquid retention and reduced clogging, enhancing the initial polishing stage and overall process efficiency.
Implementation Method 1
by reacting a polyisocyanate compound, a polyol compound and a polyamine compound, a polyurethane foamed body in which pores are formed independently is obtained
Implementation Method 2
a polyurethane composition with a silicone-based surfactant to optimize pore structure and water absorption
Data Source
Figure 1~2
Figure 3~4
AI summary
A polishing pad capable of improving an affinity to polishing liquid and stabilizing polishing performance is provided. A polishing pad 10 is equipped with a urethane sheet 2. The urethane sheet 2 has a polishing surface P for polishing an object to be polished. The urethane sheet 2 is formed by a dry molding method and is formed by slicing a polyurethane foamed body which is obtained by reacting and curing mixed liquid in which an isocyanate-group containing compound, water, a foam control agent and a polyamine compound are mixed. Foams 3 are dispersed approximately uniformly inside the urethane sheet 2. Opened pores 4 which are opened parts of the foams 3 are formed at the polishing surface P. Inside the urethane sheet 2, the foams 3 formed adjacently to each other are communicated by communication holes 9, and the communication holes 9 are formed at a ratio of 800 holes/cm2 or more when observed from a side of the polishing surface P. Polishing liquid moves via the communication holes 9 and the foams 3.