Sublimation Gas Vessel Monitoring for Accurate Residual Material Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor production is accurately measuring the residual quantity of solid materials within vessels, as direct visualization is hindered by metal construction, weight measurements are inaccurate due to heating, and cumulative flow rate calculations can result in significant errors.
Innovation Solution
A sublimation gas supply system is developed, comprising multiple solid material vessels, sublimation gas piping, a buffer tank, and pressure measuring means. This system calculates residual quantities by measuring differential pressures and consumption amounts of sublimation gas, allowing for precise determination of switching times and detecting abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If weight measurement is used to measure residual solid material, then measurement is possible, but measurement accuracy deteriorates due to heating of the vessel
Solution Approach 1:
The patent replaces the mechanical weight measurement system with a pressure-based measurement system. Pressure sensors measure the pressure of sublimation gas in the vessel, and this pressure data is used to calculate the residual solid material quantity. This substitution eliminates the direct impact of heating on measurement accuracy, as pressure measurement is not affected by thermal expansion of the vessel in the same way weight measurement is.
Solution Approach 2:
The patent introduces sublimation gas as an intermediary between the solid material and the measurement system. The gas pressure serves as an indirect indicator of the solid material quantity. By measuring the pressure of this intermediary substance rather than directly measuring the solid material or the heated vessel weight, the system achieves accurate measurement despite the heating conditions.
2Measurement precision
If cumulative flow rate calculation is used to determine residual material, then measurement is possible, but measurement precision deteriorates due to accumulation of errors
Solution Approach 1:
The patent performs preliminary measurement of the initial solid material quantity before the sublimation process begins. This initial measurement serves as a reference point, and the residual quantity is calculated by subtracting the consumed amount from this known initial value. This approach avoids cumulative errors by establishing a baseline before the process starts and only measuring changes from that baseline.
Solution Approach 2:
The patent creates a mathematical model that copies the physical relationship between solid material quantity and sublimation gas pressure. By establishing this correspondence model, the system can accurately determine residual material quantity through pressure measurements without needing to continuously integrate flow rate data, thereby avoiding cumulative errors.
3Loss of information
If direct visualization of solid material is attempted, then residual quantity can be observed, but device complexity increases due to transparent vessel requirements
Solution Approach 1:
The patent replaces the optical visualization approach with a pressure-based indirect measurement system. Instead of modifying the vessel to be transparent for visual observation, the system uses pressure sensors to measure sublimation gas pressure and calculates residual material quantity from this data. This substitution maintains the standard opaque vessel design while achieving accurate residual material measurement.
4Loss of substance
If solid material supply is interrupted to prevent waste, then material loss is reduced, but productivity deteriorates due to process interruption
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the residual solid material quantity through pressure measurements. When the residual quantity reaches a predetermined threshold, the system automatically generates a refill alert or switches to a backup vessel. This real-time feedback enables timely refilling operations without interrupting the production process, as the system can predict when material will be depleted and prepare accordingly.
Solution Approach 2:
The system performs preliminary assessment of residual material quantity and predicts when depletion will occur. By calculating the remaining usable material based on current consumption rates and pressure measurements, the system can schedule refilling operations in advance, ensuring continuous supply without interrupting the semiconductor production 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 system enables precise measurement of residual solid material quantities without the need for mass flow meters or load cells, reducing material loss and allowing for continuous sublimation gas supply by switching between solid material vessels during normal consumption or abnormal conditions.
Implementation Method 1
a sublimation gas of a solid material is supplied to a subsequent process
Implementation Method 2
pressure measuring means. This system calculates residual quantities by measuring differential pressures
Data Source
AI summary
[Problem] To provide a measuring method capable of suppressing loss of a residual quantity of a solid material inside a solid material vessel when a sublimation gas of the solid material is supplied to a subsequent process.[Solution] The method comprises, when a buffer tank is refilled with a sublimation gas: a first residual quantity calculation step in which a residual quantity of the solid material is calculated from a consumption amount of the sublimation gas fed from the buffer tank to the subsequent process; a second residual quantity calculation step in which the residual quantity of the solid material is calculated from a movement amount of the sublimation gas fed from a solid material vessel to the buffer tank; and/or a switching determination step in which a switching timing and an abnormality are determined from the residual quantity of the solid material inside the solid material vessel.