Cryopump Regeneration Control for Deterioration-Based Maintenance
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Solution Overview
Problem
Cryopumps in vacuum technology face challenges in determining the appropriate timing for maintenance due to varying deterioration rates and contamination levels, leading to increased downtime and potential unexpected failures in semiconductor manufacturing processes.
Innovation Solution
A cryopump control apparatus and method that utilizes a regeneration process with a basic purge and optional purge steps, along with a deterioration evaluation unit to monitor the number of gas purge steps and determine if the re-purge number reaches a deterioration evaluation criteria, enabling efficient tracking of cryopump deterioration and optimizing maintenance timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cryopump operates continuously without monitoring, then productivity is maintained, but reliability decreases due to unexpected failures from undetected deterioration
Solution Approach 1:
The cryopump system performs self-diagnosis by automatically monitoring its own regeneration processes and deterioration state through the control unit, which tracks purge step counts and evaluates vacuum retention without requiring external inspection systems
Solution Approach 2:
The control unit continuously monitors vacuum retention levels after regeneration and provides feedback on the deterioration state, enabling predictive maintenance scheduling based on actual pump performance rather than fixed intervals
2Reliability
If maintenance is performed frequently, then reliability is improved, but productivity decreases due to increased downtime
Solution Approach 1:
The maintenance schedule is made dynamic by adjusting it based on the actual deterioration state of the cryopump, allowing extended operation between maintenances when the pump is in good condition while ensuring timely service when deterioration accelerates
Solution Approach 2:
The system performs preliminary evaluation of vacuum retention after each regeneration process to predict future performance and schedule maintenance before actual failures occur, minimizing unexpected downtime
3Reliability
If the number of gas purge steps is increased, then reliability is improved by removing more contaminants, but loss of time increases due to longer regeneration cycles
Solution Approach 1:
The control unit dynamically adjusts the number of gas purge steps based on the detected contamination level and vacuum retention characteristics, performing more purges when needed for reliability while minimizing purges when the pump is clean, thus optimizing the balance between reliability and regeneration time
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 allows for timely detection of cryopump deterioration, reducing unexpected downtime and maintaining the vacuum processing system's efficiency by minimizing maintenance frequency while ensuring the cryopump operates in good condition.
Implementation Method 1
A cryopump accumulates gas by condensing or adsorbing gas molecules on cryopanels cooled to an ultra cold temperature
Implementation Method 2
A cryopump accumulates gas by condensing or adsorbing gas molecules on cryopanels cooled to an ultra cold temperature
Implementation Method 3
cryopanels cooled to an ultra cold temperature by a refrigerator
Implementation Method 4
the temperature of cryopanels is raised so that the gases accumulated in the cryopump are liquefied or evaporated and discharged
Data Source
AI summary
A cryopump comprises a cryopanel that cools and thus condenses or adsorbs gas, and a pump housing that contains the cryopanel. a regeneration process of the cryopump includes a basic purge process, an evacuation processes, and an optional purge process that is executed additionally if required. The optional purge process includes one or more gas purge steps. In a cryopump control apparatus that controls the cryopump, a deterioration evaluation unit determines whether a re-purge number, which is the total number of gas purge steps that are required to be executed in one regeneration process, reaches a deterioration evaluation criteria number.