Cerium Carbonate Precipitation for CMP Slurry
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Solution Overview
Problem
Existing methods for preparing cerium oxide powder for chemical mechanical polishing (CMP) face challenges such as high costs, difficulty in controlling particle size, and the generation of micro-scratches due to large particle sizes and non-uniform particle distributions, which hinder efficient polishing and selectivity.
Innovation Solution
Cerium carbonate powder is prepared through a precipitation reaction with controlled concentration and additive use to achieve uniform particle size and shape, which is then calcined to produce cerium oxide powder with desired properties, eliminating the need for lengthy milling processes and reducing micro-scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cerium oxide powder is prepared through vapor-phase process, then high purity cerium oxide can be obtained, but the preparation cost is high and large scale production is difficult
Solution Approach 1:
The patent replaces expensive vapor-phase process with a cheaper liquid-phase precipitation method using readily available cerium salts and ammonia. The process uses inexpensive chemical reagents and simple equipment to produce cerium oxide powder, eliminating the need for costly vaporization equipment and high-purity precursors while achieving comparable product quality
Solution Approach 2:
The patent changes the preparation parameters by using liquid-phase precipitation instead of vapor-phase processing. By controlling pH, temperature, and concentration parameters during precipitation, the method achieves high purity cerium oxide at lower cost and with better scalability for large-scale production
2Ease of manufacture
If cerium carbonate with large particle size is used as raw material, then the calcination process is simpler, but the resulting cerium oxide powder has large particle size that is difficult to control and requires additional filtration
Solution Approach 1:
The patent performs preliminary particle size control during the cerium carbonate precipitation process before calcination. By controlling the precipitation conditions (pH, concentration, mixing rate), uniform fine particles of cerium carbonate are formed, which then convert to uniformly sized cerium oxide particles after calcination, eliminating the need for post-calcination filtration
Solution Approach 2:
The patent changes the particle size parameters by optimizing precipitation conditions to produce fine, uniform cerium carbonate particles. This preliminary control of particle size parameters before calcination ensures that the final cerium oxide powder has the desired uniform fine particle size without requiring additional filtration steps
3Ease of manufacture
If liquid-phase process is used to prepare cerium oxide powder, then raw material and equipment costs are low, but particle size control is difficult due to uncontrolled nucleation and growth
Solution Approach 1:
The patent implements feedback control by monitoring and adjusting pH, temperature, and concentration during the precipitation process. By controlling the addition rate of ammonia and maintaining optimal pH conditions, the nucleation and growth of cerium carbonate particles are regulated, producing uniform fine particles with controlled size distribution
Solution Approach 2:
The patent successfully controls particle size parameters by optimizing precipitation conditions including pH (maintained at 9-10), temperature (room temperature to 60°C), and concentration ratios. These parameter changes enable controlled nucleation and growth, producing uniform fine cerium carbonate particles that convert to uniformly sized cerium oxide after calcination
4Productivity
If cerium oxide powder with large particle size is used for polishing, then the polishing rate is high, but micro-scratches are generated on the polished surface
Solution Approach 1:
The patent changes the particle size parameter to produce fine cerium oxide powder (0.1-10 μm, preferably 0.5-5 μm) through controlled precipitation and calcination. This optimal particle size range maintains sufficient polishing rate while eliminating micro-scratches, as the fine uniform particles can effectively polish semiconductor substrates without causing surface damage
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
This approach simplifies the preparation of CMP slurry, reduces costs, and enhances polishing rate and selectivity by maintaining uniform particle characteristics from cerium carbonate to cerium oxide, preventing micro-scratches and improving productivity.
Implementation Method 1
a method of preparing cerium carbonate powder by mixing a cerium precursor aqueous solution with a carbonate precursor aqueous solution and subjecting the mixture solution to a precipitation reaction
Implementation Method 2
when cerium oxide powder is prepared through a solid-phase reaction by calcination
Data Source
AI summary
Method of preparing cerium carbonate powder by mixing a cerium precursor solution with a carbonate precursor solution and subjecting the mixture solution to a precipitation reaction, wherein the concentration of cerium in the cerium precursor solution ranges from 1M to 10M, the molar concentration ratio of the cerium precursor to the carbonate precursor ranges from 1:1 to 1:7, and the cerium precursor solution contains at least one additive selected from the group consisting of carbonate compounds, acrylic compounds, and sulfate ion-containing compounds. The cerium carbonate powder has an orthorhombic crystal structure, a particle size of 0.05 to 1 μm, and an aspect ratio of 1 to 5. Moreover, disclosed are cerium oxide powder prepared from said cerium carbonate powder as a precursor, a preparation method thereof, and a CMP slurry containing said cerium oxide powder as an abrasive.