Ruthenium Etching Liquid Using Hypobromite to Suppress RuO4
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Solution Overview
Problem
Conventional treatment liquids for etching ruthenium from semiconductor wafers fail to achieve a balance between a sufficient etching rate and inhibition of RuO4 gas generation, leading to instability in etching rates and yield rate decreases due to RuO2 particle formation.
Innovation Solution
A treatment liquid containing a hypobromite ion, with specific concentration ranges and pH conditions, is used to etch ruthenium. This liquid also includes an oxidizing agent, such as a hypochlorite ion or ozone, to maintain the stability of the hypobromite ion and enhance the etching rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional treatment liquids are used to etch ruthenium, then the etching rate can be sufficient, but RuO4 gas is generated which causes harmful effects
Solution Approach 1:
The invention changes the chemical parameters of the treatment liquid by introducing a hypobromite ion as the key etching agent, combined with specific concentration ranges (0.01-10 wt% for hypobromite ion, 0.1-10 wt% for oxidizing agent) and pH control (8-14), to achieve high etching rates while suppressing RuO4 gas generation through controlled chemical reactions
Solution Approach 2:
The hypobromite ion acts as an intermediary substance that enables ruthenium etching through a different chemical pathway. Instead of directly using strong oxidizers that produce RuO4 gas, the hypobromite ion mediates the etching process by forming soluble ruthenium-bromine complexes, thereby achieving etching without harmful gas evolution
2Productivity
If the etching rate is increased to treat more wafers per unit time, then productivity improves, but RuO4 gas generation increases causing yield rate decrease
Solution Approach 1:
By optimizing the concentration parameters of hypobromite ion (0.01-10 wt%) and oxidizing agent (0.1-10 wt%), and controlling pH (8-14), the invention achieves a parameter combination that simultaneously enables high etching rates for increased productivity and suppresses RuO4 gas generation to maintain high yield rates
3Productivity
If the treatment liquid contains strong oxidizing agents to enhance etching rate, then productivity improves, but the treatment liquid becomes unstable and RuO4 gas is generated
Solution Approach 1:
The hypobromite ion serves as a stable intermediary that provides sustained etching capability without the instability associated with strong oxidizing agents. It reacts with ruthenium to form soluble complexes while its stability in the treatment liquid prevents unwanted side reactions and maintains consistent etching performance over time
Solution Approach 2:
The treatment liquid maintains continuous etching effectiveness through the stable presence of hypobromite ion, which continuously reacts with ruthenium surfaces. The liquid can treat multiple wafers sequentially without significant degradation in etching rate, providing continuous useful action across multiple processing steps
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 treatment liquid enables stable and high-rate etching of ruthenium while effectively inhibiting the generation of RuO4 gas, thus improving wafer treatment efficiency and reducing yield rate losses due to particle formation.
Implementation Method 1
a treatment liquid for a semiconductor with ruthenium, containing a hypobromite ion
Implementation Method 2
This liquid also includes an oxidizing agent, such as a hypochlorite ion or ozone, to maintain the stability of the hypobromite ion and enhance the etching rate
Data Source
AI summary
Provided is a treatment liquid for a semiconductor with ruthenium, containing a hypobromite ion. Also provided is a treatment liquid for a semiconductor with ruthenium, containing at least a bromine-containing compound, an oxidizing agent, a basic compound, and water which are added and mixed, wherein the liquid has the bromine-containing compound added in an amount of 0.01 mass % or more and less than 2 mass % as a bromine element content with respect to the total mass of the liquid, has the oxidizing agent added in an amount of 0.1 mass % or more and 10 mass % or less with respect to the total mass, and has a pH of 8 or more and 14 or less. Further provided is a method of producing a treatment liquid for a semiconductor with ruthenium, including a step of mixing a bromine-containing compound with a solution containing a hypochlorous acid compound and a basic compound.