Electrostatic Turbo Pump Braking for Rapid Rotor Shutdown
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional turbo pumps used in semiconductor manufacturing take a long time to slow down during maintenance and are prone to rotor-stator contact and contamination due to air backflow, leading to reduced productivity and yield.
Innovation Solution
A turbo pump design with a rotor and stator configuration that uses electrostatic forces to quickly stop the rotor and prevent contact, featuring a housing with fixed stator rings, a rotor with blades, and an electrode for electrostatic attraction, along with a valve system to manage air backflow and protect the rotor blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor speed is gradually reduced during preventive maintenance, then the rotor can slow down safely, but it takes a relatively longer amount of time which reduces productivity
Solution Approach 1:
The patent replaces the conventional mechanical braking system with an electrostatic braking system. The electrostatic brake applies electrostatic attraction force between the rotor blades and stator rings to rapidly decelerate the rotor, eliminating the need for gradual mechanical speed reduction and significantly reducing maintenance time while ensuring safe shutdown.
Solution Approach 2:
The patent changes the braking mechanism from mechanical friction-based deceleration to electrostatic force-based deceleration. By applying electrostatic attraction force, the rotor can be rapidly decelerated from high speed to stop, changing the time parameter of the shutdown process from prolonged to rapid, thus improving productivity without compromising reliability.
2Reliability
If the foreline valve is closed and the turbo pump rotor is stopped when a wafer is unloaded, then contamination is prevented, but if there is a leak in the foreline valve, the rotor may contact the stator and break
Solution Approach 1:
The patent applies preliminary anti-action by equipping the rotor with electrostatic braking capability and protective electrostatic forces. Before any potential rotor-stator contact can occur due to valve leaks, the electrostatic system is ready to rapidly decelerate the rotor or apply repulsive forces, preventing the harmful contact from happening in the first place.
Solution Approach 2:
The patent provides beforehand cushioning through the electrostatic brake system that can rapidly decelerate the rotor if abnormal conditions occur. Additionally, the electrostatic attraction/repulsion mechanism serves as a protective cushion that prevents direct mechanical contact between rotor and stator, absorbing potential impact energy before damage can occur.
3Reliability
If a high speed rotor is used to pump air or reaction gas, then a high level of vacuum is produced, but it takes a longer time to get the rotor up to speed for larger reaction chambers
Solution Approach 1:
The patent replaces conventional mechanical acceleration methods with electrostatic acceleration mechanisms. The electrostatic forces can rapidly accelerate the rotor from standstill to operating speed much faster than traditional mechanical drive systems, reducing the acceleration time parameter while maintaining the high-speed operation needed for high vacuum levels.
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 solution allows for rapid rotor slowdown during maintenance, preventing contamination and maximizing productivity by ensuring the rotor blades do not contact the stator, thus maintaining a clean environment and efficient processing.
Implementation Method 1
the blades of the rotor and the stator rings are made of a conductive material... an electrostatic brake is provided in the turbo pump... The electrostatic brake includes a power supply unit that supplies a voltage to the stator rings
Implementation Method 2
a protective electrostatic force is provided in the turbo pump... opposite voltages are applied to the rotor blades and the stator rings, thereby generating a protective electrostatic force
Data Source
AI summary
A turbo pump for evacuating a process chamber minimizes the amount time necessary to reduce the speed of the rotor in preparation for performing maintenance in the process chamber or the like. The turbo pump includes a housing communicating with the reaction chamber, a plurality of fixed stator rings spaced from one another along an inner peripheral surface of the housing, a shaft supported for rotation in the housing, a stator base surrounding the shaft and having an electric coil, a plurality of rotor blades each extending between an adjacent pair of the stator rings, and an electrode disposed at an outer peripheral surface of the housing. The electrode can receive an electric charge opposite to that applied to the rotor to forcibly stop the rotation of the rotor. Also, an electrical contact can be conductively connected to the rotor. Thus, opposite charges can be applied to the blades of the rotor and the stator to prevent the blades from contacting the stator when, for example, air backflows into the housing through a discharge port.