Substrate Gas Supply Control Using Inert Gas Feedback
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Solution Overview
Problem
Existing gas supply systems using mass flow controllers (MFCs) struggle to stably control the flow rate of gases, particularly those with challenging flow characteristics.
Innovation Solution
The system includes a process vessel for substrates, a first gas pipe for supplying process gas, a flow rate measurer, a second gas pipe for inert gas, a flow rate regulator, and a heater, allowing for precise control of the process gas flow rate by adjusting the inert gas flow rate and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mass flow controller (MFC) is used to control gas flow rate, then the device complexity is reduced, but the manufacturing precision of gas flow rate control deteriorates for gases with difficult flow characteristics
Solution Approach 1:
An inert gas is introduced as an intermediary substance to mix with the process gas in a mixing chamber. The inert gas has favorable flow characteristics that enable precise control via MFC, while the mixed gas maintains the required process gas flow rate, resolving the contradiction between simple device structure and precise flow control for difficult-to-control gases
Solution Approach 2:
The system changes the physical parameters of the gas mixture by adjusting the proportion of inert gas and process gas. By controlling the inert gas flow rate and mixing ratio, the overall flow characteristics of the mixed gas are optimized to achieve stable and precise flow rate control that neither pure process gas nor simple MFC can achieve alone
2Ease of operation
If a mass flow controller (MFC) is used to control gas flow rate, then the ease of operation is improved, but the reliability of flow rate control deteriorates for gases with difficult flow characteristics
Solution Approach 1:
The inert gas acts as a mediator that enables reliable flow control. The MFC controls the inert gas flow precisely, and through mixing with process gas, achieves reliable overall flow rate control that would be unreliable if attempting to control the process gas directly with MFC alone
Solution Approach 2:
A flow rate measurer continuously monitors the actual flow rate of the mixed gas and provides feedback to the controller. The controller adjusts the inert gas flow rate via the MFC to maintain the desired process gas flow rate, creating a closed-loop control system that ensures both ease of operation and high reliability of flow rate control
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 configuration enables stable control of gas flow rates, even for gases difficult to manage with traditional MFCs, ensuring consistent substrate processing outcomes.
Implementation Method 1
a first heater configured to adjust a temperature of the first inert gas
Implementation Method 2
a flow rate measurer provided at the first gas pipe and configured to measure a flow rate of the process gas flowing through the first gas pipe
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Provided is a technique capable of stably controlling the flow rate of a gas species, the flow rate of which is difficult to control in MFC. Thus, this substrate treatment device comprises: a treatment container for housing a substrate; a first gas pipe that supplies a treatment gas to the treatment container; a flow rate measurement unit that is provided to the first gas pipe, and that measures the flow rate of the treatment gas flowing inside the first gas pipe; a second gas pipe that is connected to the first gas pipe, and that supplies a first inert gas to a tank that retains a raw material for the treatment gas; a first flow rate adjustment unit that is provided to the second gas pipe, and that adjusts the flow rate of the first inert gas; a first heating unit that adjusts the temperature of the first inert gas; and a control unit that is configured to be capable of controlling the first flow rate adjustment unit and the first heating unit on the basis of flow rate data of the treatment gas measured by the flow rate measurement unit, so as to perform a process of supplying, to the substrate in the treatment container, the treatment gas for which at least one of the flow rate of the first inert gas and the temperature of the first inert gas is adjusted such that the flow rate of the treatment gas is a predetermined flow rate.