Magnetic Fluid Seal Heating for Low-Torque Substrate Rotation
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Solution Overview
Problem
Existing substrate processing apparatuses face high torque requirements for rotating the placing table, which necessitate large motors and transformers, leading to increased device size and energy consumption, and are prone to thermal issues due to magnetic fluid self-heating.
Innovation Solution
The apparatus incorporates heaters on the fixed shaft and housing to maintain the magnetic fluid seals at a desired temperature, reducing torque requirements and minimizing thermal expansion differences, along with a slip ring design that reduces axial height and allows for efficient power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic fluid seal is used to seal the rotation shaft, then sealing performance is improved, but torque increases due to magnetic fluid self-heating and viscosity increase
Solution Approach 1:
The patent applies temperature control to change the physical state of the magnetic fluid seal. By heating the magnetic fluid seal through a heater, the temperature is increased to reduce viscosity and prevent self-heating, thereby reducing the torque required for rotation while maintaining sealing performance
Solution Approach 2:
The patent converts the harmful effect of magnetic fluid self-heating into a beneficial effect by using an external heater to control the temperature. The heat that would normally cause viscosity increase and torque increase is now controlled to maintain optimal temperature, reducing torque while preserving sealing effectiveness
2Speed
If larger motors and transformers are used to overcome high torque, then rotational capability is improved, but device size and energy consumption increase
Solution Approach 1:
By controlling the temperature of the magnetic fluid seal to reduce viscosity, the patent reduces the torque required for rotation. This allows the use of smaller motors and transformers while maintaining the same rotational capability, thereby reducing energy consumption and device size
3Device complexity
If magnetic fluid seal operates without temperature control, then device complexity is reduced, but thermal expansion differences and torque increase
Solution Approach 1:
The patent introduces temperature control as a simple parameter adjustment mechanism. By using a heater to maintain optimal temperature of the magnetic fluid seal, the system achieves reduced torque and minimized thermal expansion differences without significantly increasing device complexity
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 reduces torque needs, enabling higher rotational speeds without lengthy warm-up times, enhances productivity, and contributes to energy savings by minimizing device size and thermal stress.
Implementation Method 1
a heater configured to adjust a temperature of the magnetic fluid seal
Implementation Method 2
a magnetic fluid seal disposed between the rotation shaft and the housing
Data Source
AI summary
Provided is a substrate treatment apparatus capable of reducing torque for rotating a placing table. This substrate treatment apparatus is provided in a treatment container and comprises: a placing table on which a substrate is placed; a rotary shaft that supports the placing table; a housing that rotatably supports the rotary shaft; a magnetic fluid seal provided between the rotary shaft and the housing; and a heater that adjusts the temperature of the magnetic fluid seal.