Plasma Chamber Cleaning Sequence for Stable TiN Etching
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Solution Overview
Problem
In semiconductor manufacturing, the etching rate of TiN films decreases over time due to the generation of boron nitride-based reaction products in the processing chamber during continuous processing, leading to changes in plasma etching performance and the deposition of foreign substances on workpieces.
Innovation Solution
A plasma processing method that involves plasma cleaning with a boron element-containing gas to remove boron elements, followed by plasma cleaning with a fluorine element-containing gas, and then depositing a silicon element-containing film to suppress the generation of boron nitride-based reaction products, thereby stabilizing the etching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma cleaning is carried out using a mixture gas containing boron trichloride gas after metal etching, then metal residue is removed from the chamber, but boron nitride-based reaction products are generated and deposited on the chamber walls and workpiece surface
Solution Approach 1:
The patent extracts and removes boron elements from the chamber using oxygen plasma treatment between the metal cleaning step and the fluoride-based plasma cleaning step. This prevents boron from reacting with nitrogen to form boron nitride deposits, while preserving the metal cleaning effectiveness of the boron trichloride-based plasma cleaning.
Solution Approach 2:
The patent introduces an intermediary oxygen plasma treatment step that acts as a mediator between the boron-containing metal cleaning step and the fluoride-based cleaning step. This intermediary step converts boron-containing deposits into removable boron oxides, preventing the formation of harmful boron nitride reaction products.
2Productivity
If continuous processing is performed to increase productivity, then manufacturing efficiency is improved, but etching rate of TiN decreases due to boron nitride accumulation
Solution Approach 1:
The patent maintains continuous processing capability by integrating boron removal treatment into the existing processing sequence. The oxygen plasma treatment is performed in-situ between processing steps, allowing continuous production without interrupting the flow or requiring chamber evacuation, thus maintaining both productivity and etching rate consistency.
Solution Approach 2:
The oxygen plasma treatment serves as an intermediary step that resets the chamber environment between continuous processing cycles. By removing boron elements after each metal cleaning step, it prevents cumulative boron nitride deposition that would otherwise degrade etching performance in subsequent batches.
3Object-generated harmful factors
If boron element-containing gas is used for metal cleaning, then metal residue removal is effective, but foreign substance deposition occurs on workpiece surface
Solution Approach 1:
The patent extracts boron elements from the chamber environment using oxygen plasma treatment. This removes the source of foreign substance deposition (boron-containing deposits) while preserving the metal cleaning effect achieved by boron trichloride-based plasma cleaning in the previous step.
Solution Approach 2:
The patent quickly removes boron elements through brief oxygen plasma treatment before they can react with nitrogen to form boron nitride foreign substances. This rapid intervention prevents the harmful reaction while maintaining the benefits of boron-based metal cleaning.
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 stabilizes the etching rate of TiN films and reduces the deposition of foreign substances, improving the reproducibility and accuracy of the etching process by maintaining a consistent plasma processing environment.
Implementation Method 1
subjecting an inside of the processing chamber to plasma cleaning using a boron element-containing gas
Implementation Method 2
removing the boron element using plasma after the plasma cleaning using the boron element-containing gas
Implementation Method 3
subjecting the inside of the processing chamber to plasma cleaning using a fluorine element-containing gas after removing the boron element
Implementation Method 4
depositing a deposited film in the processing chamber by plasma using a silicon element-containing gas
Implementation Method 5
depositing a deposited film in the processing chamber by plasma using a silicon element-containing gas
Implementation Method 6
subjecting a sample on which a metal element-containing film is disposed to plasma etching
Implementation Method 7
subjecting a sample on which a metal element-containing film is disposed to plasma etching
Data Source
AI summary
The present invention provides a plasma processing method for subjecting a sample on which a metal element-containing film is disposed to plasma etching in a processing chamber. The method comprises: subjecting an inside of the processing chamber to plasma cleaning using a boron element-containing gas; removing the boron element using plasma after the plasma cleaning; subjecting the inside of the processing chamber to plasma cleaning using a fluorine element-containing gas after removing the boron element; depositing a deposited film in the processing chamber by plasma using a silicon element-containing gas after the plasma cleaning using the fluorine element-containing gas; and subjecting the sample to plasma etching after depositing the deposited film.