CMP Slurry with Metal Borate for Hard Material Polishing
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Solution Overview
Problem
Current abrasive slurries for material removal processes, such as chemical mechanical planarization (CMP), face challenges in achieving high material removal rates while maintaining low surface roughness, especially when polishing hard materials like silicon carbide or diamond, and are often inefficient and costly.
Innovation Solution
A composition comprising abrasive particles, a multi-valent metal borate, and an oxidizing agent, which synergistically enhances the polishing efficiency by forming a multi-valent metal borate in situ, thereby improving the material removal rate and surface finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional abrasive slurries are used for polishing hard materials, then material removal operation can be performed, but the material removal rate is low and surface roughness is high
Solution Approach 1:
The patent uses a composite slurry formulation combining abrasive particles (alumina, silica, or diamond) with multi-valent metal borates (such as iron(III) borate, copper(II) borate, or zinc borate) and oxidizing agents (such as hydrogen peroxide, potassium permanganate, or sodium persulfate). This composite composition creates synergistic effects where the abrasive particles provide mechanical removal, the metal borates enhance chemical reactivity, and the oxidizing agents facilitate oxidation of the substrate surface, collectively achieving high material removal rates with smooth surface finish on hard materials like silicon carbide and diamond
Solution Approach 2:
The patent optimizes specific parameters including pH control (maintaining slurry pH between 2-10 using buffers), temperature control (heating to 40-90°C to enhance reaction kinetics), and concentration ratios (specific molar ratios of metal ions to borate ions). These parameter changes maximize the chemical mechanical polishing efficiency, enabling simultaneous achievement of high material removal rate and low surface roughness that cannot be obtained with conventional slurries
2Productivity
If polishing efficiency is enhanced for hard materials, then material removal rate increases, but cost increases and shelf-life decreases
Solution Approach 1:
The patent employs relatively inexpensive, readily available materials such as alumina or silica abrasive particles, common metal borates like iron(III) borate or zinc borate, and standard oxidizing agents like hydrogen peroxide. These materials can be sourced at low cost and provide effective polishing performance on hard substrates, making the process cost-efficient compared to using expensive specialized abrasives or proprietary polishing compounds
Solution Approach 2:
The patent implements a two-package kit system where Package A contains the abrasive particles, metal borate, and oxidizing agent, and Package B contains additional components. The packages are designed to be mixed immediately before use, ensuring the slurry maintains maximum effectiveness during the polishing operation. This preliminary preparation and controlled mixing approach prevents premature degradation while ensuring optimal performance when applied, thereby extending effective shelf-life without compromising polishing efficiency
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 achieves a high material removal rate with low surface roughness, effectively polishing hard materials like silicon carbide and diamond, and maintains efficiency over a longer shelf-life when used in a two-package kit formulation.
Implementation Method 1
a multi-valent metal borate and an oxidizing agent, which synergistically enhances the polishing efficiency by forming a multi-valent metal borate in situ
Implementation Method 2
an oxidizing agent, which synergistically enhances the polishing efficiency
Implementation Method 3
the relative movement of the slurry to a substrate to be polished assists with the planarization (polishing) process by chemically and mechanically interacting with the exterior surface of the substrate and removing unwanted material
Data Source
AI summary
A composition suitable for chemical mechanical polishing a substrate can comprise abrasive particles, a multi-valent metal borate, at least one oxidizer and a solvent. The composition can polish a substrate with a high material removal rate and a very smooth surface finish.