Semiconductor Source Gas Concentration Control via Consumption Estimation
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Solution Overview
Problem
Existing concentration control apparatuses in semiconductor manufacturing struggle to accurately maintain source gas concentration as the source quantity decreases, leading to inconsistent control due to changes in the characteristics of the concentration feedback system.
Innovation Solution
A concentration control apparatus that estimates source consumption quantity using a concentration monitor and flow rate sensors, allowing for real-time calculation of source gas concentration and consumption, enabling optimal control parameters to be set automatically, without requiring additional sensors, and includes a source consumption quantity calculator to adjust flow rates and control parameters based on calculated consumption and remaining source quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional concentration feedback control is used without source consumption estimation, then the control system is simple and does not require additional sensors, but the concentration control accuracy deteriorates as source quantity decreases
Solution Approach 1:
The system uses existing sensors (concentration monitor and flow rate sensor) to estimate source consumption quantity through calculation, rather than requiring separate dedicated sensors. The consumption quantity calculator processes data from existing measurement devices to provide source quantity information, making the existing measurement infrastructure serve dual purposes: concentration monitoring and source quantity estimation.
Solution Approach 2:
The system implements feedback control by continuously estimating source consumption quantity and using this information to adjust control parameters. The consumption quantity estimation feeds back to the control mechanism, which modifies mass flow controller settings to maintain consistent concentration control characteristics despite changing source quantity conditions.
2Measurement precision
If the same control parameters are used throughout source consumption, then the control system is simple to operate, but concentration control accuracy deteriorates as source quantity decreases
Solution Approach 1:
The control system dynamically adjusts control parameters based on real-time source consumption quantity estimation. As the source quantity changes during vaporization, the system automatically modifies mass flow controller parameters to compensate for changing vaporization characteristics, maintaining consistent control accuracy throughout the source consumption process.
Solution Approach 2:
The system changes control parameters (mass flow controller settings) based on the estimated source consumption quantity. The control mechanism receives consumption quantity information and automatically adjusts flow rate parameters to maintain optimal concentration control characteristics at different stages of source consumption.
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 allows for accurate and consistent concentration control, maintaining uniform accuracy regardless of the source quantity, by continuously updating control parameters and reflecting the state of the concentration control system in real-time.
Implementation Method 1
a concentration monitor that is provided on the source gas extraction path, and outputs output signals in accordance with a concentration of the source gas
Implementation Method 2
a source gas extraction path along which flows a source gas which is created by vaporizing the source and is then extracted from the vaporization tank
Data Source
AI summary
In order to provide a concentration control apparatus that, without adding any new sensors or the like, makes it possible to accurately estimate a quantity of source consumed inside a vaporization tank, and to perform highly accurate concentration control in accordance with the remaining quantity of source, there is provided a concentration control apparatus that, in a vaporizer that is equipped with at least a vaporization tank containing a liquid or solid source, a carrier gas supply path that supplies a carrier gas to the vaporization tank, and a source gas extraction path along which flows a source gas which is created by vaporizing the source and is then extracted from the vaporization tank, controls a concentration of the source gas and includes a concentration monitor that is provided on the source gas extraction path, and outputs output signals in accordance with a concentration of the source gas.