Fluid Supply Device Discharging Pipe Liquid Pool Freezing Prevention
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Solution Overview
Problem
The existing fluid supply devices for supercritical carbon dioxide in semiconductor manufacturing face issues with freezing of main pipes due to vaporization of liquid carbon dioxide when the system is stopped, causing failure of devices like switch valves and temperature sensors.
Innovation Solution
A fluid supply device design that includes a discharging pipe configured to create a liquid pool separating atmospheric and main pipe sides, with vaporization occurring on the atmospheric side, preventing cooling and freezing of the main pipe by maintaining the liquid on the main pipe side from vaporizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pump is disposed below the tank to allow liquid to fall down by weight, then the liquid can be supplied to the pump easily, but the liquid in the main pipe vaporizes when discharged to atmosphere causing the pipe to freeze
Solution Approach 1:
The discharge path is segmented into two separate sections: a first discharge path for liquid carbon dioxide that does not communicate with the atmosphere, and a second discharge path for vaporized carbon dioxide that opens to the atmosphere. This segmentation prevents the liquid in the main pipe from contacting atmospheric pressure, eliminating the freezing problem while maintaining the pump-below-tank configuration for easy liquid supply.
Solution Approach 2:
A discharge valve is introduced as an intermediary component between the main pipe and the atmosphere. The valve controls the discharge process by first venting pressure through a vent hole before opening the main discharge path, preventing direct atmospheric contact with liquid carbon dioxide in the main pipe and avoiding freezing of the pipe and installed devices.
2Device complexity
If the liquid carbon dioxide is discharged directly to atmosphere through a pipe, then the discharge is simple, but the liquid vaporizes causing cooling and freezing of the pipe and devices
Solution Approach 1:
The discharge system is divided into separate pathways: a first discharge path for liquid CO2 that remains isolated from the atmosphere, and a second discharge path for vaporized CO2 that communicates with the atmosphere. This segmentation allows simple direct discharge of vapor while protecting the liquid discharge path from atmospheric cooling, preventing device freezing without complicating the overall structure.
Solution Approach 2:
A vent hole is provided in the discharge valve to preliminarily release pressure and allow vapor escape before the main liquid discharge path opens. This preliminary action prevents pressure buildup and ensures smooth discharge while preventing liquid carbon dioxide from contacting the atmosphere, avoiding freezing of the pipe and devices.
3Extent of automation
If various devices are installed in the main pipe for process control, then the process can be precisely controlled, but the pipe freezing causes failure of these devices
Solution Approach 1:
The discharge system is segmented into a first discharge path for liquid carbon dioxide that maintains isolation from the atmosphere, and a second discharge path for vaporized carbon dioxide that opens to the atmosphere. This segmentation protects temperature-sensitive control devices installed in the main pipe from atmospheric cooling, ensuring reliable operation of automated control systems while enabling precise process control.
Solution Approach 2:
A discharge valve with a vent hole acts as an intermediary between the main pipe containing control devices and the atmosphere. The vent hole provides a separate pathway for pressure relief and vapor discharge, preventing direct atmospheric contact with the liquid carbon dioxide in the main pipe, thereby protecting temperature-sensitive control devices from freezing while maintaining automated process control capability.
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
Prevents the main pipe from freezing by ensuring vaporization heat from the discharging pipe vaporization does not affect the main pipe, thus avoiding device failures.
Implementation Method 1
first carbon dioxide (for example, 20° C., 5.0 MPa) in a gas state from a supply source is condensed and liquefied using a condenser
Implementation Method 2
stored in a tank, and pressure-fed to the processing chamber by a pump through a main pipe leading to the processing chamber (for example, 20° C., 20.0 MPa)
Implementation Method 3
The carbon dioxide in a liquid state fed to the processing chamber is heated (for example, 80° C., 20.0 MPa) right before the processing chamber or inside the processing chamber to form a supercritical fluid
Implementation Method 4
when the operation of the device is stopped, the carbon dioxide in a liquid state stored in the tank is brought into contact with the atmosphere through a discharge pipe connected to the main pipe, changed to a carbon dioxide in a gas state, and discharged to the outside
Implementation Method 5
the liquid stored in the tank is supplied to the pump while falling down to the main pipe by its own weight
Data Source
AI summary
A fluid supply device includes a condenser, a tank that stores the fluid, a pump that pressure-feeds the fluid toward a processing chamber, a main pipe connecting the tank and the pump and transferring the liquid stored in the tank to the pump using a weight of the liquid, and a discharging pipe that is connected to the main pipe at a lowest position of the main pipe at one end, is opened to the atmosphere at the other end, and vaporizes and discharges the liquid in the tank and the main pipe to the outside. The discharging pipe is formed so that, after the liquid in the tank and the main pipe is fully discharged, a liquid pool that separates a space on the atmosphere side and a space on the main pipe side of the discharging pipe is temporarily produced in the discharging pipe.