CMP Slurry Stabilizing Oxidizers to Prevent Metal Corrosion
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Solution Overview
Problem
Conventional CMP slurry compositions cause damage to metal layers due to varying polishing rates and excessive use of oxidizing agents, leading to electrical failures and void formation in metal plugs, and the oxidizing agents are prone to decomposition, resulting in inconsistent polishing rates.
Innovation Solution
A slurry composition incorporating an acidic aqueous solution, an amphoteric surfactant, a glycol compound, and a controlled concentration of oxidizing agents, along with an abrasive and carboxylic acid, to form a protective layer that prevents corrosion and stabilizes the oxidizing agents, ensuring consistent polishing rates and reduced void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high concentration of oxidizing agent is used to increase the polishing rate, then the polishing speed is improved, but the metal layer is etched and damaged, and voids are formed in metal plugs
Solution Approach 1:
The patent changes the concentration parameter of the oxidizing agent from high to low (0.1-5 wt% hydrogen peroxide), and introduces a catalyst (metal ions or compounds) to enhance the oxidizing activity. This parameter change resolves the contradiction by achieving effective oxidation at lower oxidizing agent concentrations, preventing metal layer damage while maintaining polishing rate.
Solution Approach 2:
The patent introduces a catalyst (metal ions such as Fe2+, Cu2+, Ni2+, or their compounds) as an intermediary substance that mediates between the oxidizing agent and the metal layer. The catalyst enhances the oxidizing activity of the peroxide, enabling effective oxidation at lower peroxide concentrations, thus preventing metal layer etching and void formation while maintaining polishing efficiency.
2Productivity
If an oxidizing agent is added to increase the polishing rate, then the polishing speed is improved, but the metal layer is corroded, resulting in electrical disconnects
Solution Approach 1:
The patent changes the concentration parameter of the oxidizing agent from high to low (0.1-5 wt% hydrogen peroxide), and introduces a catalyst (metal ions or compounds) to enhance the oxidizing activity. This parameter change resolves the contradiction by achieving effective oxidation at lower oxidizing agent concentrations, preventing metal layer damage while maintaining polishing rate.
Solution Approach 2:
The patent introduces a catalyst (metal ions such as Fe2+, Cu2+, Ni2+, or their compounds) as an intermediary substance that mediates between the oxidizing agent and the metal layer. The catalyst enhances the oxidizing activity of the peroxide, enabling effective oxidation at lower peroxide concentrations, thus preventing metal layer etching and void formation while maintaining polishing efficiency.
3Productivity
If a conventional slurry composition is used to polish the metal layer, then the polishing process can proceed, but voids are formed in the metal plug, increasing electrical resistance
Solution Approach 1:
The patent changes the concentration parameter of the oxidizing agent from high to low (0.1-5 wt% hydrogen peroxide), and introduces a catalyst (metal ions or compounds) to enhance the oxidizing activity. This parameter change resolves the contradiction by achieving effective oxidation at lower oxidizing agent concentrations, preventing metal layer damage while maintaining polishing rate.
Solution Approach 2:
The patent introduces a catalyst (metal ions such as Fe2+, Cu2+, Ni2+, or their compounds) as an intermediary substance that mediates between the oxidizing agent and the metal layer. The catalyst enhances the oxidizing activity of the peroxide, enabling effective oxidation at lower peroxide concentrations, thus preventing metal layer etching and void formation while maintaining 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 proposed slurry composition effectively prevents metal layer corrosion, stabilizes the oxidizing agents, and maintains a consistent polishing rate, reducing void formation and enhancing the efficiency of the CMP process.
Implementation Method 1
the amphoteric surfactant may be adsorbed on a surface of the metal layer to form a protective layer which serves as a corrosion inhibitor for the metal layer
Implementation Method 2
Chemical reaction between the slurry composition and materials of the wafer, coupled with mechanical polishing, result in the smoothing (planarizing) of surface features
Implementation Method 3
mechanical polishing, result in the smoothing (planarizing) of surface features
Data Source
AI summary
A slurry composition includes an acidic aqueous solution and one or both of, an amphoteric surfactant and a glycol compound. Examples of the amphoteric surfactant include a betaine compound and an amino acid compound, and examples of the amino acid compound include lysine, proline and arginine. Examples of the glycol compound include diethylene glycol, ethylene glycol and polyethylene glycol.