Core-Shell CMP Slurry for Fast Copper Polishing With Fewer Defects
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Solution Overview
Problem
Existing CMP slurry compositions for polishing copper films in semiconductor manufacturing suffer from high surface defects such as scratches, dishing, and corrosion, leading to reduced process yield and stability, and extended polishing times.
Innovation Solution
A CMP slurry composition utilizing core-shell abrasive particles with a PMMA polymer core coated with inorganic oxide, combined with a chelating agent, oxidizing agent, and corrosion inhibitor, to enhance polishing rate and reduce surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional abrasive particles are used in CMP slurry for copper film polishing, then polishing can be performed, but surface defects such as scratches, dishing, and corrosion occur frequently
Solution Approach 1:
The patent employs core-shell abrasive particles consisting of an organic polymer core (polystyrene or polyacrylic acid) coated with inorganic oxide shell (silica, alumina, or ceria). This composite structure combines the ductility of the organic core to prevent scratches with the hardness of the inorganic shell to maintain polishing rate, thereby improving surface quality without sacrificing productivity.
Solution Approach 2:
The patent modifies the physical and chemical parameters of abrasive particles by controlling the core-shell structure, including the ratio of organic core to inorganic shell, particle size distribution (0.01-10 μm), and surface charge characteristics. These parameter changes enable the particles to achieve both high polishing rate and low surface defect generation.
2Productivity
If polishing pressure is increased to improve polishing rate, then material removal speed increases, but surface defects such as scratches and erosion become more prominent
Solution Approach 1:
The core-shell structure allows the abrasive particles to withstand higher polishing pressures without deforming or generating scratches. The inorganic oxide shell provides hardness for efficient material removal, while the organic polymer core provides ductility to absorb excess stress, enabling high polishing rates with maintained surface quality.
Solution Approach 2:
The patent applies different material properties to different parts of the abrasive particle: the shell provides local hardness for cutting efficiency, while the core provides local ductility for stress absorption. This local quality differentiation enables the particles to perform high-rate polishing without generating surface defects.
3Manufacturing precision
If polishing time is extended to achieve better surface quality, then surface defects decrease, but process yield decreases and copper layer curvature or residual copper layer generation occurs
Solution Approach 1:
The core-shell abrasive particles enable simultaneous achievement of high surface quality and high process yield by removing copper material efficiently in shorter times. The inorganic shell provides effective cutting action to reduce polishing time, while the organic core prevents surface damage, eliminating the need for extended polishing that would compromise yield.
Solution Approach 2:
The patent enhances the chemical mechanical polishing process by incorporating corrosion inhibitors and chelating agents that work synergistically with the core-shell particles. This substitution of purely mechanical removal with combined chemical-chemical mechanical action accelerates copper removal while protecting the surface, reducing both polishing time and surface defects.
4Productivity
If conventional abrasive particles are used, then polishing can be performed, but copper layer curvature and residual copper layer generation occur
Solution Approach 1:
The core-shell particles with inorganic oxide shells provide uniform cutting action across the copper surface, preventing localized over-polishing that causes curvature. The organic polymer core ensures consistent particle deformation and material removal characteristics, achieving uniform copper layer thickness while maintaining high polishing efficiency.
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 composition achieves a polishing rate of 6,000 Å/min or more while minimizing scratches and corrosion on copper films, maintaining surface quality and process efficiency.
Implementation Method 1
the abrasive particles receive pressure from the polishing device to polish the surface mechanically
Implementation Method 2
chemical components contained in the polishing slurry composition cause a chemical reaction on the surface of the substrate to chemically remove a surface area of the substrate
Implementation Method 3
an oxidizing agent, and a corrosion inhibitor
Data Source
AI summary
Provided is a chemical mechanical polishing (CMP) slurry composition. The CMP slurry composition includes abrasive particles, a chelating agent, an oxidizing agent, and a corrosion inhibitor, and the abrasive particles are core-shell type particles in which a core is a polymethyl methacrylate (PMMA) polymer and a surface of the core is coated with inorganic oxide.