Polyhedral Ceria Abrasive for CMP Micro Scratch Reduction
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Solution Overview
Problem
Existing CMP processes for manufacturing NAND flash memory devices face issues with micro scratches and low polishing rates due to the use of dry ceria particles with angular grain shapes and wide grain size distributions, which increase leakage current and affect device operation.
Innovation Solution
The development of an abrasive particle with a polyhedral mother particle and auxiliary particles formed on its surface, which reduces sharp crystal faces and improves polishing efficiency by adjusting the size and distribution of the particles to minimize micro scratches and enhance polishing rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry ceria particles with angular grain shape and wide grain size distribution are used for CMP, then polishing capability is provided, but micro scratches are generated and polishing precision deteriorates
Solution Approach 1:
The invention changes the physical and chemical parameters of ceria particles by controlling particle size (5-50 nm range), crystal structure (cubic phase), and surface treatment to eliminate angular shapes. This transforms the particles from coarse angular grains to fine spherical/near-spherical particles, resolving the contradiction between polishing capability and micro scratch generation
Solution Approach 2:
The invention creates a composite slurry system combining ultrafine ceria particles with specific additives (organic acids, alcohols, water) to achieve both high polishing rate and low micro scratch generation. The composite formulation optimizes the balance between mechanical removal and chemical reaction
2Productivity
If ceria particle size is increased to improve polishing rate, then polishing speed increases, but micro scratches are sharply increased due to sharp crystal faces
Solution Approach 1:
The invention optimizes the particle size parameter to an ultrafine range (5-50 nm), which is significantly smaller than conventional ceria particles. This size reduction eliminates sharp crystal faces while maintaining high polishing rate through increased surface area and enhanced chemical reactivity
Solution Approach 2:
The invention transforms the angular polyhedral shape of conventional ceria particles into spherical or near-spherical shapes through controlled synthesis and surface treatment. This curvature elimination of sharp edges and corners directly prevents micro scratch generation while maintaining polishing effectiveness
3Manufacturing precision
If wet ceria particles with polyhedral structure are used to reduce micro scratches, then micro scratch generation decreases, but polishing rate becomes very low when particle size is not larger than 40 nm
Solution Approach 1:
The invention changes multiple parameters simultaneously: particle size (5-50 nm), shape (spherical/near-spherical), crystal structure (cubic), and surface properties. This multi-parameter optimization achieves both low micro scratch generation and high polishing rate, overcoming the limitation of conventional wet ceria particles
Solution Approach 2:
The invention utilizes the strong oxidizing capability of ultrafine ceria particles enhanced by surface treatment with organic acids and alcohols. This accelerates the chemical reaction rate at the particle surface, compensating for the reduced mechanical cutting action from smaller particle size and spherical shape
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 abrasive particle effectively reduces micro scratches and improves the polishing rate of the insulating layer, leading to enhanced device reliability and productivity by suppressing the occurrence of micro scratches and optimizing the polishing process.
Implementation Method 1
the abrasive particles mechanically polish a surface of the substrate with a pressure applied from the polishing apparatus
Implementation Method 2
chemical components contained in the slurry chemically react with the surface of the substrate to chemically remove a portion of the surface of the substrate
Data Source
AI summary
Provided are an abrasive particle including auxiliary particles formed on a surface of a mother particle, a polishing slurry prepared by mixing the abrasive particles with a polishing accelerating agent and a pH adjusting agent, and a method of manufacturing a semiconductor device in which an insulating layer is polished by the polishing slurry while using a conductive layer as a polishing stop layer.