Persulfate-Modified Silica for Tungsten CMP Metal Ion Control
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) processes for tungsten substrates using Fenton's reaction result in high residual metal ions and rapid hydrogen peroxide consumption.
Innovation Solution
A method of fabricating silica with metal ions absorbed using a solution containing persulfate salt and a metal ion source, where silica is heated with persulfate salt to create a modified silica that absorbs metal ions, reducing residual metal ions and hydrogen peroxide consumption during CMP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Fenton's reaction (Fe3+ and H2O2) is used for CMP of tungsten substrate, then polishing effectiveness is improved, but residual metal ions increase and hydrogen peroxide consumption increases
Solution Approach 1:
The patent introduces silica modified with persulfate salt as an intermediary carrier that absorbs metal ions. This mediator enables controlled metal ion release during CMP, reducing direct metal ion residues while maintaining polishing effectiveness. The silica acts as a buffer between the metal ion source and the polishing reaction.
Solution Approach 2:
The patent modifies the chemical parameters of silica by treating it with persulfate salt, creating silica with enhanced metal ion absorption capacity. This parameter change (surface modification) allows the silica to selectively absorb and control metal ion release, thereby reducing residual metal ions while maintaining CMP effectiveness.
2Productivity
If Fenton's reaction is used for CMP, then tungsten substrate polishing is achieved, but hydrogen peroxide is consumed extremely fast
Solution Approach 1:
The patent performs preliminary absorption of metal ions onto silica modified with persulfate salt before the CMP process. This preliminary action creates a reservoir of controlled metal ion release, which moderates the reaction rate with hydrogen peroxide during CMP, preventing extremely fast consumption and extending reagent durability.
3Reliability
If metal ions are added to solution for CMP, then polishing performance is improved, but residual metal ions in solution increase
Solution Approach 1:
The patent uses silica modified with persulfate salt as an intermediary carrier that binds metal ions during preparation and releases them controllably during CMP. This intermediary approach ensures metal ions are utilized effectively for polishing performance while minimizing unreacted residues in the solution.
Solution Approach 2:
The patent changes the physical state and surface properties of silica through persulfate modification, creating a material with high metal ion affinity. This parameter change enables efficient metal ion uptake and controlled release, improving polishing performance while reducing residual metal ions in the solution.
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 method significantly reduces residual metal ions in the solution and lowers hydrogen peroxide consumption during tungsten substrate polishing, making the process more efficient and cost-effective.
Implementation Method 1
The silica modified with persulfate salt absorbs the metal ions, such that the silica having metal ions absorbed thereon is obtained
Implementation Method 2
The solution is heated to react the silica with the persulfate salt
Data Source
AI summary
A silica having metal ions absorbed thereon and a fabricating method thereof are provided. The silica having metal ions absorbed thereon is a silica having metal ions absorbed thereon and being modified with persulfate salt. The method includes following steps. A solution is provided, and the solution includes silica and persulfate salt therein. The solution is heated to react the silica with the persulfate salt, so as to obtain silica modified with persulfate salt. Metal ion source is added in the solution, the metal ion source dissociates metal ions, and the silica modified with persulfate salt absorbs the metal ions to obtain the silica having metal ions absorbed thereon.