Composite Polishing Slurry for Faster 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 of insulating materials during cell formation to maintain throughput, which requires an improvement in the polishing rate for insulating materials.
Innovation Solution
A slurry containing abrasive grains with first and second particles, where the second particles include at least one metal compound such as a metal oxide or hydroxide with a metal capable of multiple valences, and a ratio of the lowest valence of 0.10 or more in X-ray photoelectron spectroscopy, is used to improve the polishing rate for insulating materials.
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 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 and structural stability, while the cerium compound particles provide chemical etching action. This composite structure enables both high polishing rate for insulating materials and broad material compatibility, resolving the contradiction between versatility and productivity
Solution Approach 2:
The invention changes the chemical composition parameters of the abrasive grains by incorporating cerium compounds with specific oxidation states (Ce3+ and Ce4+). The cerium compounds undergo redox reactions that enhance the chemical etching capability, thereby increasing the polishing rate for insulating materials while maintaining the flexibility to polish various materials
2Productivity
If cerium oxide-based polishing liquids are used to achieve high polishing rate, then the polishing rate for insulating materials improves, but the content of abrasive grains must be higher compared to silica-based liquids
Solution Approach 1:
The composite abrasive grain structure allows synergistic action between silica and cerium compound particles. The cerium compounds provide high chemical reactivity that enables effective polishing at lower concentrations, while silica particles provide mechanical support. This reduces the total abrasive grain content needed compared to pure cerium oxide-based liquids, resolving the contradiction between polishing rate and abrasive content
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 effectively enhances the polishing rate for insulating materials, enabling efficient flattening of surfaces containing silicon oxide and other insulating materials, thereby supporting the manufacturing of semiconductor elements.
Implementation Method 1
the metal compound contains a metal capable of taking a plurality of valences
Implementation Method 2
abrasive grains include first particles and second particles
Implementation Method 3
cerium oxide-based polishing liquid can polish silicon oxide at a high rate
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.