Cerium Oxide Core-Shell Particles for Uniform CMP Polishing
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Solution Overview
Problem
Existing methods for producing cerium-based core-shell particles in liquid dispersions face challenges in achieving uniform particle size distribution and high efficiency for polishing applications, particularly in the production of cerium oxide particles with controlled doping and shell formation.
Innovation Solution
A process involving the preparation of cerium oxide core particles under controlled conditions, followed by oxidation in the presence of cerium (III) salt and optional metal salt solutions under specific pH and temperature conditions, forming a cerium-based core-shell structure with precise size and doping ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce cerium-based core-shell particles, then production can be achieved, but uniform particle size distribution and high efficiency for polishing applications cannot be achieved
Solution Approach 1:
The patent applies preliminary action by first preparing cerium oxide core particles with controlled size and properties before proceeding to shell formation. The core particles are pre-synthesized with specific characteristics (average size 30-200 nm, controlled doping) to ensure uniform final product. This staged approach where core preparation precedes shell formation enables both precision and efficiency in the overall production process.
2Reliability
If cerium oxide particles are produced with controlled doping, then polishing performance is improved, but production complexity increases
Solution Approach 1:
The patent merges doping with core particle synthesis by incorporating metal dopants (such as La, Pr, Nd, Gd, or Y) directly into the cerium oxide core formation process. This simultaneous doping and core synthesis approach achieves controlled doping ratios (0.1-10 at%) while avoiding separate doping steps, thereby maintaining polishing performance without proportionally increasing production complexity.
3Manufacturing precision
If shell formation is achieved under specific pH and temperature conditions, then particle uniformity is improved, but process time and energy consumption increase
Solution Approach 1:
The patent optimizes shell formation parameters by conducting the reaction at moderate temperatures (0-80°C) and controlled pH levels (3-11). These parameter changes enable uniform shell deposition on core particles while minimizing energy consumption compared to high-temperature processes. The specific pH range ensures proper solubility and precipitation behavior for uniform shell formation without excessive energy input.
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 process yields cerium-based core-shell particles with improved uniformity and efficiency for polishing applications, offering enhanced planarization and material removal in integrated circuit fabrication.
Implementation Method 1
contacting, under oxidizing atmosphere, the aqueous dispersion with the aqueous solution(s) provided in step (a)
Implementation Method 2
providing an aqueous solution comprising a cerium (III) salt; contacting... to produce the dispersion of cerium based core-shell particles
Data Source
AI summary
The invention relates to cerium based core-shell particles having a core of cerium oxide optionally doped with at least one metal (M) and a shell consisting of a plurality of nanoparticles of cerium oxide optionally doped with at least one metal (M′), which can be the same or different from metal (M), formed on the surface of the core particle. The invention also relates to dispersions thereof in a liquid medium, to a process for producing the same and to the use of these particles and dispersions in polishing applications such as chemical mechanical polishing.