Fluoropolymer Composite CMP Pad for 3D NAND Removal Rate
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Solution Overview
Problem
Current Chemical Mechanical Planarization (CMP) processes for 3D NAND manufacturing are bottlenecked by slow removal rates during the planarization of thick dielectric layers, with conventional pads and slurries failing to achieve significant increases in removal rate without introducing polishing defects.
Innovation Solution
A polymer-polymer composite polishing pad with fluoropolymer particles embedded in a polymeric matrix, where the fluoropolymer particles have a lower tensile strength and more negative zeta potential than the matrix, is used to enhance the attraction of cationic or ceria particles, stabilizing the slurry and reducing precipitation rates, thereby increasing removal rates while maintaining low defectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing pads and slurries are used, then the CMP process is simple and easy to operate, but the removal rate is slow and becomes a bottleneck in 3D NAND manufacturing
Solution Approach 1:
The polishing pad uses a composite structure combining a polymeric matrix with embedded fluoropolymer particles. This composite material design allows the pad to achieve higher removal rates through enhanced particle attraction and slurry stabilization, while the fluoropolymer particles provide the necessary functional properties that conventional single-material pads cannot deliver.
Solution Approach 2:
The invention modifies the chemical and physical parameters of the polishing pad by incorporating fluoropolymer particles with specific properties (lower tensile strength, more negative zeta potential). These parameter changes enable the pad to stabilize cationic or ceria particle slurries and increase removal rates without compromising pad integrity.
2Productivity
If higher removal rates are achieved through process conditions or slurry design, then productivity increases, but polishing defects are introduced
Solution Approach 1:
The fluoropolymer particles act as an intermediary between the pad matrix and the slurry particles. They stabilize the cationic or ceria particles in the slurry, preventing unwanted aggregation and ensuring uniform particle distribution during polishing. This mediation enables high removal rates while maintaining surface quality and reducing defects.
3Productivity
If fluoropolymer particles are added to enhance particle attraction, then removal rate increases, but the pad structure becomes more complex
Solution Approach 1:
The fluoropolymer particles are distributed within the polymeric matrix at specific locations where they can most effectively interact with slurry particles. This localized functional enhancement allows the pad to achieve improved performance without requiring complete structural redesign, maintaining relative simplicity while delivering higher removal rates.
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 use of fluoropolymer-modified pads significantly enhances polishing rates for both cationic and ceria-containing slurries, reducing defectivity and precipitation rates, thus addressing the slow removal rate issue in CMP processes.
Implementation Method 1
the fluoropolymer particles having a zeta potential more negative than the polymeric matrix at a pH of 7... stabilizing the cationic particle-containing slurry to decrease precipitation rate of the cationic particle-containing slurry
Data Source
AI summary
The invention provides a method for polishing or planarizing a substrate. First, the method comprises attaching a polymer-polymer composite polishing pad to a polishing device. The polishing pad has a polymer matrix and fluoropolymer particles embedded in the polymeric matrix. The fluoropolymer particles have a zeta potential more negative than the polymeric matrix. Cationic particle-containing slurry is applied to the polishing pad. Conditioning the polymer-polymer composite polishing pad exposes the fluoropolymer particles to the polishing surface and creates fluoropolymer-containing debris particles in the slurry. Polishing or planarizing the substrate with the increased electronegativity from the fluoropolymer at the polishing surface and in the fluoropolymer-containing debris particles stabilizes the cationic particle-containing slurry to decreases the precipitation rate of the cationic particle-containing slurry.