Plasma Etching Process for Removing Titanium Deposits
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Solution Overview
Problem
Conventional plasma processing methods for etching substrates with insulating films and titanium-containing mask films face degradation issues over time, leading to compromised etching characteristics due to titanium-containing material deposits in the plasma processing space.
Innovation Solution
A plasma processing method involving sequential supply of fluorine-containing gases, oxygen gas, and nitrogen-containing gases to etch and remove carbon-containing and titanium-containing materials from the processing space, maintaining plasma density and substrate quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a TiN mask film is used for etching an insulating film, then the etching process can be performed with good initial characteristics, but the etching characteristics degrade over time due to titanium-containing material deposits accumulating on processing components
Solution Approach 1:
The patent applies preliminary action by performing a cleaning process before the actual etching process. Specifically, a fluorocarbon-based cleaning solution is applied to the substrate surface prior to etching to remove any pre-existing titanium-containing deposits from the mask film or processing components. This preliminary cleaning prevents the initial accumulation that would otherwise degrade etching characteristics during the etching process, thereby maintaining stable etching performance over time.
2Productivity
If the mask film is etched during the etching process, then the etching can proceed through the insulating film, but titanium-containing deposits accumulate on processing components, varying plasma density and degrading subsequent etching characteristics
Solution Approach 1:
The patent converts the harmful effect of titanium-containing material deposition into a beneficial cleaning process. The accumulated titanium deposits on the mask film and processing components, which normally degrade etching characteristics, are deliberately removed using a fluorocarbon-based cleaning solution. This cleaning process transforms the harmful accumulation into a controlled removal step, restoring the processing components to their original state and enabling consistent etching performance across multiple processing cycles.
3Productivity
If multiple lots of target substrates are processed continuously, then production efficiency is improved, but etching characteristics degrade remarkably due to cumulative deposit accumulation
Solution Approach 1:
The patent implements continuity of useful action by integrating the cleaning process into the overall etching workflow. Instead of stopping production to clean components, the fluorocarbon-based cleaning is performed periodically or continuously between substrate lots, ensuring that the processing components remain clean and ready for the next etching cycle. This continuous maintenance approach allows multiple substrates to be processed while maintaining consistent etching characteristics throughout production.
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 method effectively suppresses the degradation of etching characteristics by removing titanium-containing deposits, maintaining consistent plasma density and substrate quality even after processing multiple substrates.
Implementation Method 1
supplying a first fluorine-containing gas into the plasma processing space and etching the insulating film, with plasma of the first fluorine-containing gas
Implementation Method 2
a carbon-containing material generated from the insulating film and a titanium-containing material generated from the mask film are deposited on a member in the plasma processing space
Implementation Method 3
supplying an O2 gas into the plasma processing space and removing, with plasma of the O2 gas, the carbon-containing material to expose the titanium-containing material deposited on the member
Implementation Method 4
supplying a nitrogen-containing gas and a second fluorine-containing gas into the plasma processing space and removing, with plasma of the nitrogen-containing gas and the second fluorine-containing gas, the exposed titanium-containing material deposited on the member
Implementation Method 5
removing, with plasma of the nitrogen-containing gas and the second fluorine-containing gas, the exposed titanium-containing material
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A plasma processing method performs an etching process (S101) of supplying a first fluorine-containing gas into a plasma processing space and etching a target substrate with plasma of the first fluorine-containing gas. Then, the plasma processing method performs a carbon-containing material removal process (S102) of supplying an O2 gas into the plasma processing space and removing, with plasma of the O2 gas, a carbon-containing material deposited on a member, of which a surface is arranged to face the plasma processing space, after the etching process. Thereafter, the plasma processing method performs a titanium-containing material removal process (S103) of supplying a nitrogen-containing gas and a second fluorine-containing gas into the plasma processing space and removing, with plasma of the nitrogen-containing gas and the second fluorine-containing gas, the titanium-containing material deposited on the member after the etching process.