Tutorial Course Descriptions

Detailed Syllabus

VT-201 High Vacuum Systems and Operations

This day-long short course is intended for those who wish to understand the operation of mechanical, diffusion, and cryo pump systems, how materials are chosen, and how water vapor is pumped efficiently during the roughing cycle. It will conclude with a discussion of several diagnostic or problem solving techniques. After completion, participants should be able to explain the operation of diffusion, and cryo pumped systems; have a basic understanding of vacuum materials; understand how water vapor is pumped without condensing on interior surfaces, and have thought about some approaches to solving problems with non-performing systems.

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:

1. Introduction
This section describes basic terms, components and system concepts that all participants should understand.

  • Basic definitions: Ideal gas, pressure, speed, conductance, and such
  • Describe common vacuum system configurations and applications
  • Outline the 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 and gas ballast
  • Piston pump
  • 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 operating principles of a typical diffusion pumped system.

  • Diffusion pump construction and operating principle
  • Backstreaming, baffles and traps
  • Starting, cycling and stopping a diffusion pump system
  • Preventing oil migrating from pumps to chamber
  • Preventive maintenance issues

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 cryo pumped system are described here.

  • Refrigerator and pump construction
  • Cryocondensation and cryosorption pumping
  • Pumping array designs
  • Refrigerator operation
  • Starting, cycling, and stopping a helium cryo pump
  • Regeneration and maintenance

5. Materials in Vacuum
Materials used in vacuum are carefully chosen for their compatibility with the environment and process. This section reviews properties of materials and how they are selected for use in chambers, valves, seals, and feed-through components.

  • Metals, glasses and ceramics
  • Polymers and elastomers, and their use in valves and gaskets
  • Cleaning, and outgassing: how they affect operation

6. Rough Pumping Large Systems
Modern production systems are designed for a specific application, and because of their differences, roughing systems are no longer follow rules described in older textbooks. This section describes roughing techniques for several vacuum pumping systems and applications.

  • 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
Systems are never free of problems. Although proper design and operation will minimize down time, systems will fail. Frequently, process engineers focus on process parameters as being the cause of poor quality product; however, vacuum-related parameters are just as likely to be a culprit. This section presents some introductory approaches to solving problems related to the vacuum system, and concludes with three case studies.

  • Diagnostic ideas for dealing with operating and non-operating systems
  • Case study: Unintended consequence of a system’s installation
  • Case study: Improper maintenance
  • Case study: Improper change of a system set-point

Instructor: John F. O’Hanlon, Professor Emeritus of Electrical and Computer Engineering, University of Arizona
John F. O’Hanlon

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

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