VT-201 Vacuum Systems, Materials, and Operation
This full-day course is intended for those who wish to understand the operation of mechanical, diffusion, and cryo-pumped systems, how materials are chosen, and how water vapor is pumped efficiently during the roughing cycle. It will conclude with a brief discussion of diagnostic methods. This course will benefit operators, engineers, and maintenance personnel, because proper understanding of complex vacuum systems leads to higher production yields, shorter down times, and improved reliability.Topical Outline:
Introduction to vacuum systems
- Rotary mechanical pumps
- Diffusion pumps and systems
- Cryogenic pumps and systems
- Turbomolecular pumps and systems
Attendees in this tutorial receive the text, A User’s Guide to Vacuum Technology, 3rd edition, John O’Hanlon (John Wiley & Sons, 2003).Course Details:
This section describes basic terms, components and system concepts that all should understand.
- Basic definitions: ideal gas, pressure, speed, conductance, etc.
- Descriptions of common system configurations and applications
- Functions of each system component
2. Rotary Mechanical Pumps
The construction, characteristics, operating principles, and applications of the several commonly used mechanical pumps are reviewed here.
- Rotary vane pumps
- Roots and claw pumps
- Screw, scroll, and diaphragm pumps
3. Diffusion Pump Systems
This section covers the construction and operating principles of the diffusion pump, and the operation of a typical diffusion pumped system.
- Construction and operating principle
- Backstreaming, baffles and traps
- Starting, cycling and stopping
- Preventing oil migrating
- Preventive maintenance
4. Cryopump Systems
The construction, characteristics, and operating principles of the helium-gas-refrigerated cryo pump, and the construction and operating principles of a typical cryopumped system are described here.
- Refrigerator and compressor construction
- Cryo-condensation and cryo-sorption
- Pumping array
- Refrigerator operation
- Starting, cycling, and stopping
- Regeneration and maintenance
5. Materials in Vacuum
Materials used in vacuum are carefully chosen for their compatibility with environment and process. This section reviews properties and selection of materials used in chambers, valves, seals, and feedthroughs.
- Metals, glasses and ceramics
- Polymers and elastomers
- Valves and gaskets
- Cleaning, and outgassing
6. Rough Pumping Large Systems
Production systems are designed for specific applications; therefore, roughing systems no longer look like, or are operated like, those described in old books. This section describes roughing techniques for cryo- and diffusion-pumped systems.
- Preventing water aerosol formation and particle deposition
- Roughing to high-vacuum crossover in a diffusion pumped system
- Roughing to high-vacuum crossover in a cryo-pumped system
- Pumping large, multi-chamber systems
7. Diagnostic Ideas
Although proper design and operation minimizes down time, product occasionally can be out of specification. Frequently, staff considers the culprit to be a process parameter; however, a vacuum-related issue are also a cause. This section suggests a diagnostic approach to solving operational problems and demonstrates this approach with three historical examples.
- Installation error
- Maintenance error
- Operator error
is Professor Emeritus of Electrical and Computer Engineering, the University of Arizona. He retired from IBM Research Division in 1987, where he was involved in thin-film deposition, vacuum processing, and display technology. He retired from UA in 2002, where he directed the NSF Ind./Univ. Center for Microcontamination Control. His research focused on particles in plasmas, cleanrooms, and ultrapure water contamination. He is the author of A User’s Guide to Vacuum Technology, 3rd edition. (John Wiley & Sons, 2003).
This course is currently available via:
On Location Education Program