Multivalent Metal Oxide Slurry for High-Rate Insulator 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 of insulating materials during cell formation to maintain throughput, and to improve the polishing rate for insulating materials.
Innovation Solution
A slurry containing abrasive grains with at least one metal compound selected from metal oxides or hydroxides, where the metal can take multiple valences, and the slurry yields a ratio of 0.13 or more in X-ray photoelectron spectroscopy for the lowest valence of the metal when in contact with a polished surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional silica-based polishing liquids are used, then the polishing process is flexible and can handle various materials, but the polishing rate for insulating materials is insufficient to resolve high level differences rapidly
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 with Ce3+ and Ce4+ states). This parameter change enables the polishing liquid to achieve both high adaptability to various materials and high polishing rates for insulating materials, resolving the contradiction between versatility and productivity
Solution Approach 2:
The invention creates a composite polishing liquid system that combines metal compounds with multiple valences, abrasive grains, and various additives (such as chelating agents, surfactants, and pH buffers). This composite formulation achieves synergistic effects that simultaneously provide broad material compatibility and high polishing rates for insulating materials
2Productivity
If cerium oxide-based polishing liquids are used to improve polishing rate, then the polishing rate for insulating materials increases, but the composition becomes more specific and less flexible
Solution Approach 1:
The invention adjusts the valence state parameters of cerium and other metal compounds to optimize performance. By controlling the ratio of different valence states (e.g., Ce3+ to Ce4+), the polishing liquid achieves high polishing rates while maintaining broad adaptability to different materials including insulating materials, electroconductive materials, and semiconductors
Solution Approach 2:
The invention designs metal compounds with multiple valences to perform multiple functions simultaneously: they act as abrasive grains for mechanical removal, provide chemical etching through redox reactions, and enable adaptability to various materials. This multi-functionality resolves the contradiction between high polishing rate and broad material compatibility
3Productivity
If higher abrasive grain content is used to increase polishing rate, then the polishing rate improves, but the flexibility and controllability of the polishing process decreases
Solution Approach 1:
The invention changes the chemical reactivity parameters by introducing metal compounds with multiple valences that can adjust their chemical activity based on local conditions (pH, oxidation state, surface chemistry). This allows high polishing rates to be achieved through enhanced chemical-mechanical interaction rather than simply increasing abrasive grain content, thereby maintaining process flexibility and controllability
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 described slurry significantly improves the polishing rate for insulating materials, enabling efficient polishing of insulating materials like silicon oxide at high rates.
Implementation Method 1
the metal compound contains a metal capable of taking a plurality of valences... CMP (Chemical mechanical polishing) technology... can polish silicon oxide at a high rate
Implementation Method 2
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
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.