Mass Flow Controller Correction for Vaporized Raw Material
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Solution Overview
Problem
Existing substrate processing technologies face challenges in stabilizing the supply of vaporized raw materials during film-forming processes, particularly due to variations in the remaining amount of solid raw materials, leading to inconsistent flow rates and film quality issues.
Innovation Solution
A method involving a mass flow controller and mass flow meter to adjust the carrier gas flow rate, with correction factors calculated based on measurement values to ensure the vaporized raw material flow rate matches a target value, and periodic recalibration to account for changes in raw material availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a correction factor is stored in advance to control the vaporized raw material flow rate, then the flow rate can be controlled initially, but the correction factor becomes inaccurate when the remaining amount of solid raw material varies
Solution Approach 1:
The system measures the actual flow rate of the vaporized raw material using a mass flow meter and feeds this information back to the control unit. The control unit then adjusts the carrier gas flow rate based on this feedback to maintain the desired vaporized raw material flow rate, ensuring accurate control regardless of raw material remaining amount
Solution Approach 2:
The system performs a dummy process before actual substrate processing to measure and determine the appropriate correction factor or flow rate parameters. This preliminary action ensures that the control parameters are optimized for the current raw material state before real processing begins
2Ease of operation
If the carrier gas flow rate is adjusted using a fixed correction factor, then the initial flow rate control is simple, but the vaporized raw material flow rate becomes unstable when raw material amount changes
Solution Approach 1:
The correction factor is changed from a static, pre-stored value to a dynamic parameter that is updated based on the current raw material state. The system continuously or periodically recalibrates the correction factor to reflect changes in raw material remaining amount, maintaining flow rate stability while keeping the control system relatively simple
3Measurement precision
If the device is stopped to reset the correction factor when raw material is drastically decreased, then the correction factor accuracy is maintained, but processing time is lost
Solution Approach 1:
The system performs flow rate measurements and correction factor recalibrations during the processing operation itself, specifically during dummy processes that occur between actual substrate processing steps. This allows the correction factor to be continuously updated without stopping the overall processing workflow, maintaining both accuracy and productivity
4Quantity of substance
If the vaporization amount of raw material increases temporarily at the start of processing, then the raw material supply is sufficient initially, but the flow rate deviates from the target value based on the stored correction factor
Solution Approach 1:
The system performs a dummy process at the beginning of processing to measure the actual vaporized raw material flow rate and determine the appropriate correction factor before actual substrate processing begins. This preliminary calibration accounts for temporary increases in vaporization amount, ensuring accurate film thickness control from the first substrate
Solution Approach 2:
The system uses real-time flow rate measurements during the dummy process to adjust the carrier gas flow rate and establish an accurate correction factor, creating a feedback loop that ensures the vaporized raw material flow rate matches the target value before production processing begins
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 approach stabilizes the supply of vaporized raw materials, ensuring consistent film formation quality by accurately adjusting the carrier gas flow rate in response to changes in raw material availability, thereby improving the processing of multiple substrates.
Implementation Method 1
supplying a carrier gas having a flow rate adjusted by a mass flow controller to a raw material container
Implementation Method 2
supplying a vaporized raw material obtained by vaporizing a solid or liquid raw material inside the raw material container
Implementation Method 3
via a raw material gas supply path in which a mass flow meter is installed
Data Source
AI summary
A method of processing each of a plurality of substrates comprises: obtaining a first correction factor based on a first flow rate set value of a mass flow controller and a first measurement value of a mass flow meter; adjusting the first flow rate set value of the mass flow controller with the first correction factor so that the flow rate of the vaporized raw material becomes equal to a target value to process the substrate; obtaining a second correction factor based on a second flow rate set value of the mass flow controller and a second measurement value of the mass flow meter; and adjusting the second flow rate set value of the mass flow controller with the second correction factor so that the flow rate of the vaporized raw material becomes equal to the target value to process the substrate.