Substrate Processing Apparatus Dynamic Etching Control
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Solution Overview
Problem
Conventional substrate processing apparatuses face challenges in achieving high selectivity during etching of silicon nitride films while preventing silicon oxide precipitation on silicon oxide films, which affects the accuracy and efficiency of the etching process.
Innovation Solution
A substrate processing apparatus and method that control the phosphoric acid and silicon concentrations in the etching liquid over time, adjusting the concentrations in stages to improve selectivity and prevent silicon oxide precipitation, by using a processing unit and control unit to manage the etching liquid composition and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the etching processing progresses in a substrate processing apparatus using phosphoric acid, then the silicon nitride film is etched, but a silicon oxide may be precipitated on the silicon oxide film
Solution Approach 1:
The patent changes the concentration parameters of the processing liquid over time. Specifically, it adjusts the phosphoric acid concentration and silicon-containing compound concentration in different stages of the etching process. By dynamically changing these parameters, the patent prevents silicon oxide precipitation while maintaining effective etching of the silicon nitride film.
Solution Approach 2:
The patent applies preliminary action by adding a silicon-containing compound to the phosphoric acid processing liquid before the etching process begins. This preliminary preparation of the processing liquid composition prevents silicon oxide precipitation during the etching process by controlling the chemical environment in advance.
2Productivity
If the phosphoric acid concentration is maintained high throughout the etching process, then the etching rate is maintained, but the selectivity between silicon nitride film and silicon oxide film deteriorates
Solution Approach 1:
The patent applies dynamics by making the processing liquid composition changeable over time during the etching process. The phosphoric acid concentration and silicon-containing compound concentration are adjusted in different stages, transforming the static processing condition into a dynamic one that adapts to the progress of etching, thereby maintaining both high etching rate and high selectivity.
Solution Approach 2:
The patent segments the etching process into multiple stages with different processing liquid compositions. By dividing the continuous etching process into distinct phases with optimized conditions for each phase, the patent achieves both high overall etching rate and high selectivity in different stages of the process.
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 approach enables high-accuracy etching with improved selectivity and suppresses silicon oxide precipitation, maintaining process uniformity and efficiency throughout the etching process.
Implementation Method 1
an etching processing of selectively etching, between a silicon nitride film (SiN) and a silicon oxide film (SiO2) formed on a substrate, the silicon nitride film by immersing the substrate in a phosphoric acid processing liquid
Implementation Method 2
since a silicon component is eluted from the substrate as the etching processing progresses
Implementation Method 3
there is a concern that a silicon oxide (SiO2) may be precipitated on the silicon oxide film
Data Source
AI summary
A substrate processing apparatus includes a processing unit and a control unit. The processing unit is configured to perform an etching processing by immersing a substrate in a processing liquid containing phosphoric acid and a silicon-containing compound. The control unit is configured to control the processing liquid such that the substrate is processed, in a first processing time of the etching processing, with the processing liquid having a first phosphoric acid concentration and a first silicon concentration, and the substrate is processed, in a second processing time later than the first processing time, with the processing liquid having a second preset phosphoric acid concentration lower than the first phosphoric acid concentration and a second preset silicon concentration lower than the first silicon concentration or with the processing liquid having the second preset phosphoric acid concentration and the first silicon concentration.