Multivalent Oxide Slurry for Faster CMP of Insulating Films
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Solution Overview
Problem
In the manufacturing of semiconductor elements, particularly with 3D-NAND devices, there is a need to rapidly address 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 metal oxides and hydroxides, is used, where the ratio of the lowest valence of the metal is 0.13 or more as measured by X-ray photoelectron spectroscopy, enhancing the polishing rate by facilitating bonding and removal of insulating material surfaces.
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
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing liquid by introducing metal compounds with multiple valences (such as cerium oxide with Ce3+ and Ce4+). This chemical parameter change enables significantly higher polishing rates for insulating materials while maintaining the ability to polish various materials through appropriate selection of metal compounds and process conditions.
Solution Approach 2:
The patent uses composite abrasive grains containing metal compounds (e.g., cerium oxide) combined with other materials. These composite abrasive grains provide both high polishing rate for insulating materials and versatility for different material types, resolving the contradiction between polishing rate and material compatibility.
2Productivity
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 patent achieves high polishing rates through changing the chemical nature of the abrasive grains (using metal compounds with multiple valences) rather than simply increasing abrasive grain content. This allows maintaining low abrasive grain content while achieving high polishing rates, thereby preserving process flexibility and controllability.
3Productivity
If cerium oxide-based polishing liquid is used to achieve high polishing rate, then the polishing rate for insulating materials improves, but the control over polishing conditions becomes more difficult
Solution Approach 1:
The patent utilizes the redox chemistry of metal compounds with multiple valences (particularly cerium oxide with Ce3+/Ce4+ couples). By controlling pH, oxidizing agents, and reducing agents, the valence ratio can be precisely adjusted to achieve desired polishing rates while maintaining excellent process control and repeatability.
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 processing of insulating materials in semiconductor manufacturing, including STI and interlayer insulating materials, by optimizing the valence ratio of the metal compounds in the abrasive grains.
Implementation Method 1
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
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.