Multi-Valence CMP Slurry for Faster Insulating Material Polishing
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Solution Overview
Problem
In the manufacturing of semiconductor elements, particularly for 3D-NAND devices, there is a need to rapidly resolve high level differences in insulating materials during the CMP process to maintain throughput, and existing polishing technologies do not adequately improve the polishing rate for insulating materials.
Innovation Solution
A slurry containing abrasive grains with metal compounds that can take multiple valences, specifically cerium oxide and hydroxide, is used, where the ratio of the lowest valence of the metal is 0.13 or more, as measured by X-ray photoelectron spectroscopy, to enhance the polishing rate of insulating materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional silica-based polishing liquids are used, then polishing can be achieved for a wide variety of materials, but the polishing rate for insulating materials is insufficient
Solution Approach 1:
The invention changes the chemical composition parameters of the polishing liquid by incorporating metal compounds with multiple valences (such as cerium oxide, cerium hydroxide, or mixed valence states) instead of conventional silica-based abrasives. This parameter change enables significantly higher polishing rates for insulating materials while maintaining broad material compatibility through the unique chemical reactivity of multi-valent metal compounds
Solution Approach 2:
The invention uses composite abrasive grains containing metal compounds with multiple valences (e.g., cerium oxide mixed with cerium hydroxide, or combinations with other metal compounds). These composite materials combine mechanical abrasion with chemical reactions at different valence states, achieving both high polishing rate and versatility across different material types
2Productivity
If higher abrasive grain content is used to increase polishing rate, then material removal speed improves, but flexibility of use and control over polishing characteristics are reduced
Solution Approach 1:
The invention changes the chemical mechanism from purely mechanical abrasion to chemical-mechanical interaction through multi-valent metal compounds. This allows achieving high polishing rates at lower abrasive grain contents because the chemical reactivity (redox reactions between different valence states) enhances material removal efficiency, thereby maintaining flexibility in formulation and application
3Productivity
If cerium oxide-based polishing liquid is used to achieve high polishing rate, then insulating material polishing improves, but the complexity of slurry composition increases
Solution Approach 1:
The invention utilizes the natural multi-valence property of cerium (Ce³⁺ and Ce⁴⁺ states) and other metals to create a chemically active polishing system. By controlling the ratio of different valence states (maintaining lowest valence ratio ≥0.13), the system achieves high polishing rates through redox reactions without requiring complex additive packages, keeping the formulation relatively simple while highly effective
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 slurry significantly improves the polishing rate for insulating materials, enabling efficient polishing of silicon oxide and other insulating materials, thereby enhancing the manufacturing process for semiconductor elements.
Implementation Method 1
the metal compound contains a metal capable of taking a plurality of valences
Implementation Method 2
measuring a valence of a metal contained in the abrasive grains by X-ray photoelectron spectroscopy
Data Source
AI summary
A slurry containing abrasive grains and a liquid medium, in which the abrasive grains contain at least one metal compound selected from the group consisting of a metal oxide and a metal hydroxide, the metal compound contains a metal capable of taking a plurality of valences, and when the slurry is brought into contact with a surface to be polished to bring the abrasive grains into contact with the surface to be polished, the slurry yields 0.13 or more in X-ray photoelectron spectroscopy as a ratio of the lowest valence among the plurality of valences of the metal.