Thermosetting Polyurethane Polishing Pad Curative Ratio
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) pads face a trade-off between achieving high removal rates, excellent planarization efficiency, and low defectivity, with existing pads often falling short in one or more of these categories, requiring additional polishing steps that increase costs.
Innovation Solution
A thermosetting polyurethane polishing pad is developed using an isocyanate-terminated urethane prepolymer and a curative mixture of polyamine and cyclohexanedimethanol, with a molar ratio of polyamine to cyclohexanedimethanol ranging from 20:1 to 1:1, which balances bulk pad hardness for efficient planarization and surface asperity softness for reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If harder polishing pad materials are used, then removal rate and planarization efficiency improve, but defectivity increases
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing pad by using a specific ratio of polyamine curative (20-50 wt%) to cyclohexanedimethanol curative (5-80 wt%) in the thermosetting polyurethane formulation. This parameter optimization enables the pad to achieve both high removal rate and low defectivity simultaneously by controlling the crosslinking density and surface properties.
Solution Approach 2:
The patent creates a composite curing system combining two different curatives (polyamine and cyclohexanedimethanol) with an isocyanate-terminated urethane prepolymer. This composite material approach allows the polishing pad to exhibit dual characteristics: hardness for efficient planarization and controlled surface asperity softness for reduced defectivity.
2Object-affected harmful factors
If softer polishing pad materials are used, then defectivity decreases, but removal rate and planarization efficiency worsen
Solution Approach 1:
The patent optimizes the curative ratio parameters to achieve the desired balance. By adjusting the polyamine to cyclohexanedimethanol ratio within the specified ranges, the pad formulation achieves softer surface asperities that reduce defects while maintaining sufficient bulk hardness for effective planarization through the thermosetting polyurethane structure.
Solution Approach 2:
The composite curing system with dual curatives creates a polishing pad with differentiated mechanical properties: the bulk material provides structural support and hardness, while the surface asperities exhibit softer characteristics due to the specific curative composition, enabling low defectivity without sacrificing removal rate.
3Object-affected harmful factors
If additional polishing steps are implemented, then defectivity is reduced, but process complexity and cost increase
Solution Approach 1:
The patent develops a universal polishing pad formulation that performs multiple functions simultaneously: it provides high removal rate, excellent planarization, and low defectivity in a single pad type. This multi-functional pad can be used across different polishing steps (oxide removal, CMP, etc.), eliminating the need for multiple specialized pads and reducing process complexity.
Solution Approach 2:
By optimizing the chemical composition parameters (curative ratios, prepolymer selection), the patent creates a polishing pad with balanced properties that can handle multiple polishing requirements, reducing the need for additional polishing steps and simplifying the overall manufacturing process.
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 provides both high removal rates and low defectivity, enhancing planarization efficiency and pad life while minimizing the need for additional polishing steps, making it suitable for advanced node semiconductor applications.
Implementation Method 1
The polishing layer includes an isocyanate-terminated urethane prepolymer, a polyamine curative, and a cyclohexanedimethanol curative
Data Source
AI summary
A chemical-mechanical polishing pad comprising a thermosetting polyurethane polishing layer includes an isocyanate-terminated urethane prepolymer, a polyamine curative, and a cyclohexanedimethanol curative. The polyamine curative and the cyclohexanedimethanol curative are in a molar ratio of polyamine curative to cyclohexanedimethanol curative in a range from about 20:1 to about 1:1.