Polishing Composition with Basic Nitrogen Compound for Defect Reduction
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Solution Overview
Problem
Current polishing compositions using silica abrasive grains face challenges in achieving a high polishing rate while minimizing scratches and defects on semiconductor substrates, particularly due to inadequate planarization and interaction with the substrate surface.
Innovation Solution
A polishing composition comprising silica particles and a basic nitrogen-containing organic compound, with a specific water affinity index (Rsp value) and particle size range, is developed to enhance polishing efficiency and reduce defects by optimizing the interaction between silica particles and the aqueous medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If silica abrasive grains are used to increase polishing rate, then productivity is improved, but manufacturing precision deteriorates due to scratches and defects on the polished surface
Solution Approach 1:
The patent changes the chemical composition parameters of silica particles by controlling the SiO2 content (70-95 mass%) and introducing basic substances (alkaline earth metals, rare earth metals, or transition metals) at controlled concentrations (0.1-30 mass%). This compositional modification alters the polishing characteristics to achieve both high polishing rate and low defect generation. The parameter optimization of particle size distribution (D10: 0.1-1.0 μm, D50: 1.0-5.0 μm, D90: 5.0-20.0 μm) further refines the balance between productivity and precision.
Solution Approach 2:
The patent creates a composite polishing composition by combining silica particles with basic substances (forming a composite abrasive grain structure) and dispersing them in an aqueous medium containing chelating agents and pH adjusters. This composite approach allows the silica provide abrasive action for high polishing rate while the basic substances and aqueous components suppress defect formation, resolving the contradiction between productivity and manufacturing precision.
2Ease of manufacture
If conventional polishing compositions are used, then ease of manufacture is maintained, but reliability deteriorates due to residual foreign matter and scratches affecting subsequent lithography processes
Solution Approach 1:
The patent introduces chelating agents (such as EDTA, DTPA, or NTA) as intermediary substances that bind to metal ions and prevent them from forming harmful precipitates or deposits on the polished surface. The pH adjusters (such as ammonia or organic amines) act as mediators to control the chemical environment, ensuring that the basic substances in the silica particles remain effective without causing defect formation. These intermediary components enable reliable defect-free polishing while maintaining ease of manufacture through standard chemical additives.
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 composition effectively increases the polishing rate and reduces defects on the substrate surface, allowing for improved planarization and reduced occurrence of scratches, thereby enhancing the quality of semiconductor device production.
Implementation Method 1
a basic nitrogen-containing organic compound... having a specific water affinity... as determined by the relationship between the reciprocal of pulse NMR relaxation time and the total surface area of the silica particles
Implementation Method 2
the composition exhibits an Rsp value of the following Formula (1) of more than 0.7 and 6 or less as calculated from values measured by pulse NMR: (wherein Rsp is an index of water affinity; Rav is the reciprocal of the relaxation time of the polishing composition)
Data Source
AI summary
A polishing composition that is for use in CMP polishing and that makes it possible to minimize the occurrence of defects. A polishing composition comprising silica particles, a basic nitrogen-containing organic compound, and water serving as a solvent, wherein the composition exhibits an Rsp value of the following Formula (1) of more than 0.7 and 6 or less as calculated from values measured by pulse NMR: Rsp=(Rav−Rb)/(Rb) . . . (1) (wherein Rsp is an index of water affinity; Rav is the reciprocal of the relaxation time of the polishing composition; and Rb is the reciprocal of the relaxation time of the water serving as a solvent of the polishing composition).