Diamond Polishing Composition for Scratch-Free SiC Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polishing methods for polycrystalline SiC substrates face challenges in achieving a smooth surface finish without scratches due to abrasive grain aggregation and poor dispersibility, particularly with small particle sizes, and mechanical polishing leaves cutting marks and processing distortions.
Innovation Solution
A polishing composition comprising diamond abrasive grains with a size range of 10 nm to 1 µm, polyhydric alcohol, pure water, and dispersants such as organic acid salts, inorganic acid salts, or octylphenol ethoxylate-based surfactants, to enhance dispersibility and prevent agglomeration, ensuring a smooth surface without scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP polishing is used to achieve low surface roughness on polycrystalline SiC substrates, then surface smoothness is improved, but the polished surface exhibits irregularities along grain boundaries due to different etching rates of crystal grains
Solution Approach 1:
The patent replaces CMP (chemical mechanical polishing) with pure mechanical polishing using diamond particles. This substitution eliminates the chemical etching component that causes differential etching rates among crystal grains, thereby avoiding surface irregularities along grain boundaries while still achieving the required surface roughness of 0.1-0.5 nm
Solution Approach 2:
The patent changes the polishing mechanism from chemical-mechanical to pure mechanical by selecting appropriate diamond particle sizes (0.01-0.4 mass% with D50 of 10 nm-1 µm) and using a mechanical polishing process without chemical agents, fundamentally altering how material removal occurs to prevent grain boundary irregularities
2Manufacturing precision
If mechanical polishing with small particle size abrasive grains is used to reduce scratches, then surface smoothness is improved, but abrasive grains aggregate and settle in the dispersion medium, causing deeper scratches
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance in the polishing composition. This dispersant prevents aggregation and settling of diamond abrasive grains in the liquid medium, ensuring uniform distribution and stable suspension of fine particles, thereby enabling the use of small particle size abrasives without the harm of agglomeration
Solution Approach 2:
The patent creates a composite polishing composition consisting of diamond abrasive grains dispersed in a liquid medium with added dispersant. This composite formulation combines multiple components to achieve both effective material removal and stable dispersion, preventing the aggregation issue that would otherwise occur with fine abrasive particles
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 suppresses abrasive grain agglomeration, improves dispersibility, and achieves a highly smooth polished surface on polycrystalline SiC substrates, reducing or eliminating scratches.
Implementation Method 1
a dispersant, wherein the content of the diamond abrasive grain is 0.01-0.4 mass%, wherein the average particle diameter D50 of the diamond abrasive grain is 10 nm-1 µm
Implementation Method 2
mechanical polishing using a combination of diamond particles and a metal surface plate
Data Source
AI summary
[Abstract] Provided is a polishing composition that suppresses the generation of abrasive grain agglomerates, has good dispersibility of abrasive grains, and is capable of obtaining a highly smooth surface without generating polishing scratches on the surface to be polished. The polishing composition comprising; a diamond abrasive grain, a polyhydric alcohol, pure water, and a dispersant, wherein a content of the diamond abrasive grain is 0.01-0.4 mass%, wherein an average particle size D50 of the diamond abrasive grains is 10 nm-1 µm, wherein the content of the polyhydric alcohol is 1 to 40 mass%, and wherein the dispersant is at least one of an organic acid salt, an inorganic acid salt, and an octylphenol ethoxylate-based surfactant.