CMP Pad Dual Curative System Defect Reduction
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) pads often result in polishing defects such as scratches and chatter marks during the planarization of semiconductor wafers, while also requiring improvements in removal rate and defect reduction.
Innovation Solution
A CMP pad with a polishing layer formed from a reaction product of an isocyanate terminated urethane prepolymer and a curative system comprising a sulfur containing diamine curative and a high molecular weight polyol curative, with a specific weight ratio and molecular characteristics to enhance polishing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CMP pads are used, then polishing process can be performed, but polishing defects such as scratches and chatter marks are formed
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing pad by using a dual curative system (sulfur-containing diamine and high molecular weight polyol) with specific molecular weights and hydroxyl group counts. This chemical parameter change modifies the pad's physical properties to reduce defects while maintaining surface quality
Solution Approach 2:
The patent creates a composite curative system combining two different curatives (sulfur-containing diamine and high molecular weight polyol) with specific weight ratios. This composite approach leverages the complementary properties of each curative to simultaneously reduce defects and maintain manufacturing precision
2Reliability
If polishing pad formulation is optimized for defect reduction, then polishing defects are reduced, but removal rate may decrease
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: curative molecular weight (2,500-100,000), hydroxyl group count (3-10 per molecule), and weight ratio (3:10 to 7:10). This multi-parameter optimization achieves defect reduction while maintaining removal rate through balanced chemical composition
Solution Approach 2:
The patent applies different curative components with specific local characteristics to different aspects of pad performance. The sulfur-containing diamine provides defect reduction properties while the high molecular weight polyol maintains structural integrity for adequate 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 described CMP pad significantly reduces polishing defects such as scratches and chatter marks while maintaining or improving removal rates, thereby enhancing the planarization process for semiconductor wafers.
Implementation Method 1
a polishing layer formed from a reaction product of an isocyanate terminated urethane prepolymer and a curative system
Data Source
AI summary
A chemical mechanical polishing pad comprising a polishing layer which comprises a reaction product of an isocyanate terminated urethane prepolymer; and a curative system comprising a sulfur containing diamine curative, and a high molecular weight polyol curative, wherein the high molecular weight polyol curative can have reduced polishing defects. The high molecular weight polyol curative has a number average molecular weight of 2,500 to 100,000; and an average of 3 to 10 hydroxyl groups per molecule. The weight ratio of the high molecular weight polyol curative to the sulfur containing diamine curative is in the range of 3:10 to 7:10.