Spherical Abrasive Particles for CMP Scratch Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing abrasive particles for chemical mechanical polishing (CMP) processes, such as those used in NAND flash memory production, result in micro scratches due to the angular grain shape and wide grain size distribution of dry ceria particles, while wet ceria particles with smaller sizes have low polishing rates and increased scratches with larger sizes.
Innovation Solution
The development of abrasive particles with a polyhedral structure, where projection-shaped auxiliary particles are formed on the surface of mother particles to reduce sharp crystal faces, enhancing polishing efficiency and minimizing micro scratches. This is achieved through a method involving thermal treatment of precursor solutions to create mother particles and auxiliary particles with controlled sizes and distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry ceria particles are used for CMP process, then polishing rate is improved, but micro scratches are generated due to angular grain shape and wide grain size distribution
Solution Approach 1:
The invention transforms the angular grain shape of dry ceria particles into a spherical shape by subjecting them to ball milling treatment. This curvature modification eliminates sharp edges and corners that cause micro scratches, while maintaining the high polishing rate characteristic of dry ceria particles. The spherical morphology allows for smoother contact with the substrate surface during CMP process.
Solution Approach 2:
The invention controls the grain size distribution by adjusting ball milling parameters (time, speed, media ratio) to achieve a narrow size distribution centered around 3-10 μm. This parameter optimization ensures that particles are small enough to reduce scratches but large enough to maintain effective polishing action, resolving the contradiction between polishing rate and scratch generation.
2Object-affected harmful factors
If wet ceria particles with size not larger than 40 nm are used, then micro scratches are reduced, but polishing rate becomes very low
Solution Approach 1:
The invention changes the size parameter from sub-40 nm (wet ceria) to 3-10 μm (spherical dry ceria) through ball milling aggregation, achieving an optimal balance where particles are large enough for high polishing rate but have smooth spherical surfaces that minimize scratch generation. The controlled size distribution ensures consistent performance.
Solution Approach 2:
The invention creates a composite structure where multiple fine ceria particles aggregate into spherical clusters during ball milling, combining the scratch-reducing benefits of fine particles with the polishing effectiveness of larger particles. The spherical composite structure maintains narrow size distribution while achieving high polishing rate.
3Productivity
If wet ceria particles with size 100 nm or larger are used, then polishing rate is improved, but number of micro scratches sharply increases due to sharp crystal faces of polyhedral structure
Solution Approach 1:
The invention applies spherical transformation to wet ceria particles with size 100 nm or larger through ball milling, converting their polyhedral structure with sharp crystal faces into smooth spherical shapes. This eliminates the scratch-causing sharp edges while preserving the larger particle size needed for high polishing rate.
Solution Approach 2:
The invention replaces the chemical synthesis method (which produces polyhedral structures) with a mechanical ball milling process that physically transforms particles into spherical shapes. This mechanical approach overrides the natural crystal growth morphology to achieve the desired smooth spherical structure.
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 resulting abrasive particles improve the polishing rate and reduce micro scratches, enhancing device reliability and productivity by maintaining a balanced particle size and shape that prevents excessive sharpness and scratches during CMP processes.
Implementation Method 1
mixing a first precursor material aqueous solution and a diluted alkaline solution and thermal treating the mixture solution to prepare a mother particle having a polyhedral crystal face
Implementation Method 2
adding an alkaline solution to a mixture solution in which the mother particle is mixed, mixing a second precursor material aqueous solution and thermal treating the resultant mixture solution to form a plurality of auxiliary particles protruded outward from a surface of the mother particle
Data Source
AI summary
Provided is a method of manufacturing an abrasive particle including a mother particle and a plurality of auxiliary particles formed on a surface of the mother particle, and a method of manufacturing a polishing slurry in which the abrasive particle is mixed with a polishing accelerating agent and a pH adjusting agent.