Thermal Oxide Film Thickness Control via Pre-Clean Oxide Correlation
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Solution Overview
Problem
The variation in thermal oxide film thickness after cleaning is unpredictable, making it difficult to control the thermal oxidization process and achieve uniformity and reproducibility in forming thin films on semiconductor substrates.
Innovation Solution
A method involving correlation acquisition, cleaning condition determination, and thermal oxide film formation steps to establish a correlation between the constitution, OH groups, stoichiometric proportions, or hydrogen content of the chemical oxide film and the thickness of the thermal oxide film, allowing for precise control of the cleaning process to achieve a predetermined thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods are used to form chemical oxide films, then cleaning is achieved, but the thickness of the subsequent thermal oxide film varies unpredictably
Solution Approach 1:
The invention measures the thickness of the chemical oxide film formed by cleaning in advance, before performing thermal oxidization. This preliminary measurement allows the thermal oxidization conditions to be adjusted based on the actual starting film thickness, enabling predictable control of the final thermal oxide film thickness despite variations in the chemical oxide film formation process.
Solution Approach 2:
The invention changes the parameters of the thermal oxidization process based on the measured chemical oxide film thickness. By adjusting thermal oxidization time, temperature, or atmosphere according to the preliminary measurement, the final thermal oxide film thickness can be precisely controlled to achieve the target value with high uniformity and reproducibility.
2Measurement precision
If the thickness of natural oxide film or chemical oxide film is measured, then film composition is known, but this does not predict the thickness of thermal oxide film after oxidization
Solution Approach 1:
The invention introduces a feedback mechanism where the measured thickness of the chemical oxide film is used to adjust the thermal oxidization process parameters. This closed-loop control ensures that variations in the chemical oxide film are compensated for during thermal oxidization, maintaining consistent final film thickness across different batches and conditions.
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
Enables the formation of thermal oxide films with thin target thickness and excellent reproducibility, facilitating control of the thermal oxidization process.
Implementation Method 1
a chemical oxide film formed by cleaning
Implementation Method 2
subjecting the plurality of semiconductor substrates to a thermal oxidization treatment
Implementation Method 3
thermal oxidization treatment conditions
Data Source
AI summary
The present invention is a method for forming a thermal oxide film on a semiconductor substrate, including: a correlation acquisition step of providing a plurality of semiconductor substrates each having a chemical oxide film having a different constitution formed by cleaning, performing a thermal oxidization treatment under identical thermal oxidization treatment conditions to form a thermal oxide film, and determining a correlation between the constitution of the chemical oxide film and a thickness of the thermal oxide film in advance; a cleaning condition determination step of determining the constitution of the chemical oxide film based on the correlation obtained in the correlation acquisition step so that a thickness of a thermal oxide film to be formed on a semiconductor substrate is a predetermined thickness, and determining cleaning conditions for forming a chemical oxide film having the determined constitution of the chemical oxide film; a substrate cleaning step of cleaning the semiconductor substrate under the determined cleaning conditions; and a thermal oxide film formation step of performing a thermal oxidization treatment on the cleaned semiconductor substrate under conditions identical to the thermal oxidization treatment conditions in the correlation acquisition step to form a thermal oxide film on a surface of the semiconductor substrate. Consequently, a thermal oxide film is formed with the target film thickness with excellent reproducibility.