Composite CMP Slurry for Fast Insulating Material Planarization
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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, as conventional polishing methods are inefficient in addressing these challenges.
Innovation Solution
A slurry containing abrasive grains with first and second particles, where the second particles are metal compounds capable of taking multiple valences, with a ratio of the lowest valence of 0.10 or more in X-ray photoelectron spectroscopy, is used to improve the polishing rate of insulating materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
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 in 3D-NAND devices
Solution Approach 1:
The polishing liquid uses composite abrasive grains comprising both silica particles and cerium compound particles. The silica particles provide mechanical abrasion while the cerium compound particles (with multiple valences) provide chemical etching action. This composite structure enables high polishing rates for insulating materials while maintaining controlled polishing characteristics, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The invention changes the chemical composition parameters of the abrasive grains by incorporating cerium compounds with specific multiple valence states (Ce3+ and Ce4+). The ratio of lowest valence (0.10 or more) provides optimal chemical reactivity with insulating materials. This parameter optimization enables rapid removal of high level differences while maintaining polishing quality, achieving both high productivity and reliable performance.
2Productivity
If higher abrasive grain content is used to increase polishing rate, then the polishing speed improves, but the flexibility and controllability of the polishing process decreases
Solution Approach 1:
The invention partially replaces mechanical abrasion (silica-based) with chemical etching (cerium compound-based). The cerium compounds react chemically with insulating materials through redox reactions, enabling high polishing rates without requiring high abrasive grain content or high mechanical pressure. This substitution maintains process flexibility and controllability while achieving high productivity.
3Productivity
If cerium oxide-based polishing liquids are used to achieve high polishing rate, then the polishing speed for insulating materials improves, but the ability to polish electroconductive materials and other materials is reduced
Solution Approach 1:
The polishing liquid achieves multi-functionality by combining silica particles (effective for both insulating and electroconductive materials) with cerium compound particles (optimized for insulating materials). This composite abrasive system enables the same polishing liquid to effectively process various material types including insulating materials, electroconductive materials, and organic resin materials, maintaining high adaptability while achieving high polishing rates for insulating materials.
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 enhances the polishing rate for insulating materials, enabling efficient flattening of surfaces in semiconductor manufacturing, particularly for STI and interlayer insulating materials, by facilitating effective bonding and removal mechanisms.
Implementation Method 1
the metal compound contains a metal capable of taking a plurality of valences, and a ratio of the lowest valence among the plurality of valences of the metal is 0.10 or more in X-ray photoelectron spectroscopy
Data Source
AI summary
A slurry containing abrasive grains and a liquid medium, in which the abrasive grains include first particles and second particles in contact with the first particles, the second particles 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 a ratio of the lowest valence among the plurality of valences of the metal is 0.10 or more in X-ray photoelectron spectroscopy.