Onium-Ion Filtration Lubricant for Stable Ru Etching
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the decrease in onium ion concentration during filtration, leading to surface roughening and generation of harmful RuO4 gas, which affects etching efficiency and yield.
Innovation Solution
A smoothing agent for filtration is developed with controlled surface tension (60-75 mN/m) containing onium ions and hypohalous acid ions, which maintains onium ion concentration and prevents RuO4 gas generation by interacting with metal surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If filtration is performed to remove particles in treatment liquid, then particle removal is improved, but onium ion concentration decreases
Solution Approach 1:
The patent changes the surface tension parameter of the treatment liquid by adding a surfactant, adjusting it to 60-75 mN/m. This parameter change prevents onium ion adsorption onto the filter surface during filtration, thereby maintaining onium ion concentration while still achieving effective particle removal through the filter.
2Productivity
If onium ion concentration decreases during filtration, then filtration efficiency is improved, but surface smoothness deteriorates
Solution Approach 1:
The patent adjusts the surface tension parameter to 60-75 mN/m by adding surfactant, which changes the interfacial properties between the treatment liquid and filter surface. This prevents onium ion adsorption, maintaining sufficient onium ion concentration to ensure surface smoothness while allowing filtration to proceed efficiently.
3Ease of manufacture
If treatment liquid is reused to reduce manufacturing cost, then cost is reduced, but etching rate decreases
Solution Approach 1:
The patent maintains the surface tension parameter within 60-75 mN/m throughout the treatment liquid's lifecycle by adding surfactant. This prevents onium ion loss during filtration and reuse cycles, maintaining consistent etching characteristics and rate even after multiple reuse cycles, thereby enabling cost-effective liquid reuse without productivity loss.
4Productivity
If Ruthenium is wet-etched under alkaline conditions to achieve high etching rate, then etching speed is improved, but RuO4 gas generation increases
Solution Approach 1:
The patent converts the harmful RuO4 gas generation into a beneficial process by controlling the onium ion concentration through surface tension adjustment. The maintained onium ion concentration suppresses RuO4 gas formation while preserving the high etching rate of Ruthenium under alkaline conditions, effectively converting a harmful side reaction into a controlled process.
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 solution maintains surface smoothness, prevents RuO4 gas formation, and enhances etching characteristics, improving semiconductor wafer yield and reducing manufacturing costs through effective reuse of treatment liquids.
Implementation Method 1
a surface tension at 25° C. is 60 mN/m or more and 75 mN/m or less
Implementation Method 2
Adding an onium ion to a semiconductor treatment liquid and passing the liquid through a filter
Implementation Method 3
the liquid containing a hypobromite ion, exhibiting an excellent etching rate and stability of the etching rate, and capable of preventing generation of RuO4 gas
Data Source
AI summary
Provided is, for example, a lubricant for filtration which has a surface tension of 60-75 mN/m and which contains onium ions. Also provided are a composition for polishing which contains onium ions and hypohalous acid ions, a metal recovery agent which contains onium ions coordinated to metal oxide ions or metal hydroxide ions, and the like.