Polyurea Polishing Pad with Fluorocarbon Segments for CMP
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Solution Overview
Problem
Current Chemical Mechanical Planarization (CMP) processes for 3D NAND manufacturing are bottlenecked by slow removal rates, particularly during the Pre-Metal Dielectric (PMD) step, due to limitations in conventional dielectric CMP slurries and polishing pads, which hinder the advancement to higher layer counts in memory devices.
Innovation Solution
Development of a polyurea polishing pad with a soft segment copolymer containing fluorine-free aliphatic groups and fluorocarbon, cured with a curative agent and incorporating gas or liquid-filled polymeric microelements, which remains hydrophilic during polishing, enhancing ceria slurry interactions and increasing removal rates without altering the pad's composition or introducing negative effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional dielectric CMP slurries and polishing pads are used, then the CMP process can be performed, but the removal rate is slow and becomes a bottleneck in 3D NAND manufacturing
Solution Approach 1:
The patent modifies the polishing pad material composition by incorporating fluorocarbon-containing soft segments into the polyurea matrix, changing the chemical and physical parameters of the pad to enhance slurry interaction and increase removal rate by 20-30%
Solution Approach 2:
The invention uses a composite polyurea structure combining hard segments with fluorocarbon-containing soft segments, creating a material that maintains structural integrity while enhancing chemical interaction with ceria slurry particles for improved polishing efficiency
2Productivity
If the polishing pad material is modified to increase removal rate, then productivity improves, but the pad must maintain its hydrophilic properties and surface energy to prevent negative effects
Solution Approach 1:
The patent introduces fluorocarbon-containing soft segments specifically in the polishing layer of the polyurea pad, creating a localized region with enhanced slurry interaction properties while maintaining the overall hydrophilic character of the pad through controlled composition and structure
3Productivity
If higher removal rates are achieved through process conditions or slurry design, then productivity increases, but the PMD step remains bottlenecked without fundamental pad improvement
Solution Approach 1:
The patent achieves higher removal rates through fundamental material parameter changes in the polishing pad rather than increasing process complexity, allowing existing CMP equipment and slurry formulations to operate more effectively
Solution Approach 2:
The invention focuses on improving the consumable polishing pad rather than modifying expensive or complex equipment, providing a cost-effective solution that can be implemented through material substitution
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 polyurea polishing pad achieves a 20-30% increase in removal rate with cationic ceria particles and improved thermal stability, while maintaining hydrophilicity and surface energy, facilitating efficient CMP processes for higher layer counts in 3D NAND manufacturing.
Implementation Method 1
the polymeric microelements in the transition region having decreased thickness as it approaches the polishing layer with thickness of the compressed microelements adjacent the polishing layer being less than fifty percent of the diameter of the polymeric microelements in the bulk region
Implementation Method 2
the polymeric microspheres being fractured at the polishing layer during polishing
Implementation Method 3
the soft segment being a copolymer of aliphatic fluorine-free polymer groups and a fluorocarbon having a length of a least six carbons wherein the polishing layer remains hydrophilic during polishing in shear conditions
Data Source
AI summary
The invention provides a polishing pad suitable for polishing at least one of semiconductor, optical, magnetic or electromechanical substrates. It includes a polyurea polishing layer and a polyurea matrix. The polyurea has a soft segment being a copolymer of aliphatic fluorine-free polymer groups and a fluorocarbon having a length of a least six carbons. The polyurea matrix being cured with a curative agent and including gas or liquid-filled polymeric microelements. The polyurea matrix has a bulk region and a transition region adjacent the bulk region that extends to the polishing layer. The polymeric microelements in the transition region decrease in thickness as they approach the polishing layer with thickness of the compressed microelements adjacent the polishing layer being less than fifty percent of a diameter of the polymeric microelements in the bulk region. The polishing layer remains hydrophilic during polishing in shear conditions.