Abrasive-Bound Chelators for CMP Metal Removal
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Solution Overview
Problem
Current chemical mechanical planarization (CMP) slurries using soluble metal ions for enhanced polishing rates lead to substrate contamination and difficulties in metal ion recovery due to the mobility and strong bonding of chelating agents, resulting in increased costs and environmental challenges.
Innovation Solution
The method involves immobilizing ligand-containing organic compounds on the surface of abrasive particles via a chemical reaction with positively charged stabilizer-modified abrasives, using aluminum, tungsten, or boron-containing stabilizers, which are bound to the abrasive via covalent bonds, allowing for controlled and effective chelation of metal ions during CMP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If soluble chelating agents are used in CMP slurry to enhance metal removal rate, then polishing efficiency is improved, but substrate contamination and metal ion recovery difficulty increase
Solution Approach 1:
The patent uses abrasive particles as intermediaries to carry chelating agents from the slurry to the substrate surface. The chelating agents are adsorbed onto the abrasive particle surfaces, which then deliver them directly to metal sites during polishing. This intermediary approach maintains the beneficial chelation effects while preventing free soluble chelators from contaminating the substrate and complicating metal ion recovery.
Solution Approach 2:
The chelating agents are localized onto the surface of abrasive particles rather than being uniformly distributed as soluble compounds. This local concentration on particle surfaces ensures chelating activity occurs precisely where metal removal happens, improving polishing efficiency while minimizing overall contamination and facilitating easier separation and recovery of metal ions from the slurry.
2Productivity
If soluble chelating agents are used to solubilize abraded metal ions, then metal removal rate increases, but chelator removal from waste stream becomes difficult
Solution Approach 1:
Abrasive particles serve as intermediaries that adsorb chelating agents, converting them from soluble free-floating compounds into particle-bound forms. This transformation maintains the chelating function for enhancing metal removal rates while enabling easy separation of chelators with the abrasive particles from the waste stream through filtration or sedimentation, greatly simplifying metal ion recovery processes.
Solution Approach 2:
The patent facilitates the discarding of used abrasive particles (which carry bound chelators) from the slurry system, while enabling recovery of valuable metal ions. The particle-bound chelators are easily separated with the discarded abrasives, and metal ions can be recovered from the clarified slurry without complex separation processes required for soluble chelator systems.
3Productivity
If strong bonding between chelating agents and metal ions occurs, then metal removal rate enhances, but chelator removal from polished surfaces becomes difficult
Solution Approach 1:
The abrasive particles act as intermediaries that bind chelating agents, creating a controlled delivery mechanism to metal sites. This intermediary approach allows strong chelation at the substrate surface for enhanced metal removal while the chelators remain associated with the abrasive particles, making them easier to remove from polished surfaces compared to freely soluble chelators that penetrate and bond strongly to the substrate.
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
This approach reduces substrate contamination, simplifies the removal of chelators from polished surfaces and waste streams, and enhances the recovery of metal ions, thereby improving the efficiency and environmental sustainability of the CMP process.
Implementation Method 1
the stabilizer is bound to the abrasive, preferably by a covalent bond
Implementation Method 2
method for fixing and immobilizing ligand-containing organic compounds on the surface of an abrasive via chemical reaction with positively charged stabilizer-modified abrasive
Implementation Method 3
said ligands having a capacity to chelate one or more metal ions
Data Source
AI summary
A method of polishing a substrate with a polishing composition comprising an oxidizing agent and abrasive particles having a surface, said surface of the abrasive particles being at least partially modified with 1) at least one stabilizer compound comprising aluminum, boron, tungsten, or both, said stabilizer compound being bound via a covalent bond to said abrasive particles, and 2) an organic chelating compound, said chelating compound being bound via a covalent bond to said stabilizer compound. The organic chelating compounds include one or more of 1) a nitrogen-containing moiety and between one and five other polar groups; 2) a sulfur-containing moiety and between one and five other polar groups; and 3) between two and five polar groups selected from carboxylic acid groups or salts thereof and hydroxyl groups.