Vacuum Pump Stop Control Using Reverse Rotation to Prevent Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor manufacturing, vacuum pumps face issues with solidification and liquefaction of gas components during operation, leading to deposition of reaction products in the pump's gaps, which can prevent reactivation and necessitate frequent maintenance or replacement, causing prolonged suspension of manufacturing processes.
Innovation Solution
A control device and system that utilize a decision unit to analyze past state quantities and normal fluctuation ranges of a vacuum pump's state quantities, adjusting motor control methods during the stop process to prevent deposition and facilitate reactivation, including changes in motor output, rotation direction, and ON/OFF periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vacuum pump operates at high temperature to prevent solidification and liquefaction of gas components, then good vacuum evacuation is achieved, but the pump body and components are subjected to thermal stress and energy consumption increases
Solution Approach 1:
The control device performs preliminary cooling of the vacuum pump after operation by controlling the motor to rotate in the reverse direction, which prevents solidification and liquefaction of gas components before they can accumulate in harmful quantities, thereby reducing the need for continuous heating during operation
Solution Approach 2:
The control device implements periodic reverse rotation of the motor at predetermined intervals during operation, creating cyclical cooling effects that prevent accumulation of solidified and liquefied components, allowing the pump to maintain reliable vacuum evacuation performance with reduced continuous heating
2Reliability
If the vacuum pump is stopped to perform maintenance or replacement due to deposition of solidified and liquefied products, then the pump reliability is restored, but the manufacturing process is suspended
Solution Approach 1:
The control device performs preliminary reverse rotation cooling of the vacuum pump after each operation cycle, which prevents solidification and liquefaction of gas components before they can accumulate to levels requiring maintenance, thereby maintaining pump reliability and avoiding manufacturing process suspension
Solution Approach 2:
The control device ensures continuous protection against component deposition by implementing reverse rotation cooling after every operation, whether the pump is stopped for reactivation or maintenance, thereby maintaining continuous manufacturing process operation without interruptions for pump maintenance or replacement
3Reliability
If the motor is controlled to rotate in reverse direction for cooling, then deposition of reaction products is prevented, but the device complexity and control difficulty increase
Solution Approach 1:
The control device implements a simple predetermined control pattern that automatically rotates the motor in reverse direction for a predetermined period after operation stops, providing effective cooling and prevention of product deposition through straightforward timing-based control logic
Solution Approach 2:
The control device uses periodic reverse rotation at predetermined intervals with fixed durations, creating a simple rhythmic control pattern that effectively prevents deposition while maintaining minimal control system complexity through repetitive, predictable operation cycles
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 increases the probability of reactivating vacuum pumps, reducing the frequency of maintenance and replacement, thereby minimizing downtime and maintenance costs in semiconductor manufacturing.
Implementation Method 1
a motor that rotationally drives the rotor
Implementation Method 2
the above-described vacuum pump generates compressive heat during the process of transferring gas, so that the vacuum pump in operation is at a high temperature to some extent
Data Source
AI summary
A control device that controls a target vacuum pump including a motor, including: a decision unit that decides, using at least one of target state quantities at a time of a past stop process of the target vacuum pump or another vacuum pump wherein the target state quantities are state quantities which fluctuate in accordance with a load at a time of a process of stopping a vacuum pump, a normal fluctuation range or a normal time fluctuation behavior of the target state quantity at the time of the stop process; and a control unit that controls the motor, wherein the control unit compares the target state quantity at the time of the process of stopping the target vacuum pump with the normal fluctuation range or the normal time fluctuation behavior, and changes a method of controlling the motor during the stop process depending on the comparison result.