Nitrogen-Enhanced Thermal Oxidation for Semiconductor Films
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Summary
Problems
Forming a uniformly thin thermal oxide film on semiconductor substrates with good reproducibility is challenging due to variations in natural and chemical oxide films, and existing methods struggle to maintain detergency while controlling film thickness accurately.
Innovation solutions
A method involving correlation acquisition steps to determine optimal drying and thermal oxidation conditions based on OH group amounts and drying conditions, allowing for the formation of thermal oxide films with intended thickness without altering the cleaning chemical solution composition.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If thermal oxidation is performed in a conventional furnace atmosphere, then oxidation proceeds uniformly, but oxidation resistance treatment is insufficient and defects occur at the interface between the oxidized film and semiconductor substrate
Why choose this principle:
The patent changes the atmospheric parameters by introducing a controlled concentration of nitrogen dioxide (NO2) into the oxidation atmosphere. This parameter change enables the formation of a nitrogen-containing oxidized film that provides both oxidation resistance and interface defect prevention, resolving the contradiction between oxidation resistance and interface quality.
Principle concept:
If thermal oxidation is performed in a conventional furnace atmosphere, then oxidation proceeds uniformly, but oxidation resistance treatment is insufficient and defects occur at the interface between the oxidized film and semiconductor substrate
Why choose this principle:
Nitrogen dioxide acts as an intermediary substance in the oxidation atmosphere. It mediates between the oxygen supply and the semiconductor substrate, forming a nitrogen-containing oxidized film that prevents interface defects while maintaining oxidation resistance. The NO2 serves as a chemical mediator that transforms the oxidation process to achieve both goals simultaneously.
Application Domain
Data Source
AI summary:
A method involving correlation acquisition steps to determine optimal drying and thermal oxidation conditions based on OH group amounts and drying conditions, allowing for the formation of thermal oxide films with intended thickness without altering the cleaning chemical solution composition.
Abstract
The present invention provides a method for forming a thermal oxide film, comprising the steps of: a step of acquiring a first correlation between an amount of OH groups and thickness of the thermal oxide film by forming a thermal oxide film by thermal oxidation treatment under the same condition after preparing a plurality of semiconductor substrates having chemical oxide films formed by cleaning and having different amounts of OH groups; a step of acquiring a second correlation between an amount of OH groups and drying conditions by cleaning under the same cleaning condition followed by changed drying conditions to substrates and measuring amounts of OH groups; a step of acquiring a third correlation between drying condition and thickness of thermal oxide film by using the first correlation and the second correlation; a step of determining drying condition and thermal oxidation condition by using the third correlation; a step of cleaning the substrates; and a step of drying and a thermal oxide film formation after the cleaning step using the drying conditions and thermal oxidation treatment conditions determined in the drying and thermal oxidation treatment condition determination step. This provides a method for forming thermal oxide film in which a thermal oxide film can be formed with intended thickness with good reproducibility while without changing the composition of the cleaning chemical solution.