- Course Number:
- MT 223
- Course Title:
- Vacuum Technology
- Credit Hours:
- Lecture Hours:
- Lecture/Lab Hours:
- Lab Hours:
- Special Fee:
Course DescriptionCovers the theory and practice of vacuum as used in semiconductor manufacturing. Topics include vacuum principles, vacuum systems and their components such as pumps, gauges and valves, and finally vacuum trouble- shooting. Prerequisites: MT 101, MT 102, (MT 103 or MT 104), CH 100 or higher, WR 121, or instructor permission. Audit available.
Intended Outcomes for the course
- Apply basic vacuum principles such as the behavior of gas and behavior of a vacuum system while evaluating a pump down.
- Consider basic mechanisms and characteristics of vacuum system components such as pumps, valves and gauges while troubleshooting.
- Be able to perform basic operations of a vacuum system such as measuring pressure correctly, venting a vacuum system, a rough pump down and a high vacuum pump down with correct valving sequence.
- Be able to perform simple maintenance of vacuum systems including installation or replacement of various pipes, fittings, valves, gauges, and simple pumps.
- Be able to perform vacuum trouble-shooting including leak isolation and detection.
Course Activities and Design
This course will include a variety of learning activities. The
lecture portion of the course, three hours per week, will include
instructor delivered lectures and demonstrations stressing key
topics in the course. In preparation for the lecture portion of
the course, students will be expected to complete all reading and
The laboratory portion of the course, three hours per week, will
include laboratory activities. The purpose of the laboratory
activities is to develop skills in the operation of basic vacuum
systems and analyzers, teamwork, and communicating in oral and
Outcome Assessment Strategies
Assessment of student performance in this course will be conducted
in both the lecture and laboratory portions of the course and may
be in the form of written and/or practice-based questions.
Course Content (Themes, Concepts, Issues and Skills)
REQUIRED STUDENT COMPETENCIES:
1.0 Property of Gases
1.1 Define the terms: pressure and vacuum.
1.2 Convert pressure units between the following systems of
units: torr, pascal, mbar, atm, and mm of Hg.
1.3 State the following laws for pressure-volume-temperature
relationships for a fixed amount of gas:
(a) Boyle's Law
(b) Charles' Law
(c) Gay-Lussac's Law
1.4 State the ideal gas law.
1.5 Solve for pressure, temperature, molecular mass, and volume
of a gas using the ideal gas law.
1.6 State Avogadro's Principle for equal volumes of gases.
1.7 State Dalton's Law of Partial Pressure as it relates to a
mixture of gases.
1.8 State Graham's Law of Effusion.
1.9 State the main ideas that form the basis for the Kinetic
Theory of Gases.
1.10 Draw a graph to illustrate the distribution of kinetic
energies in a collection of gas molecules at three different
1.11 List the gaseous components and percent composition of air
(excluding water vapor as a component).
1.12 Define the term "Standard Temperature and Pressure" or STP.
1.13 Calculate the "mean free path" of a given gas at a given
temperature and pressure.
1.14 List the four different pressure ranges of vacuum systems:
low, medium, high, and ultra-high.
1.15 State the relationship of vacuum ranges to semiconductor
processes, e.g. photolithography, etch, diffusion, deposition,
ion implant, and metallization.
2.0 Gas Flows
2.1 Define the following types of gas flows: turbulent, viscous,
intermediate, and molecular.
2.2 Relate the different types of gas flows to the following
pressure regions: low, high, and ultra-high.
2.3 Define the terms: throughput and conductance.
2.4 Given a component catalog or data sheet, find the conductance
value for a given vacuum system component.
3.0 Gas Sources
3.1 Define the following terms: volume gas, surface gas, and
3.2. Give examples of where volume gases, surface gases, and
monolayers occur in a vacuum system.
3.3 Relate surface gas composition variations to pumping time.
3.4 Define the term: rate-of-rise.
3.5 Given pressure versus time data, construct a log-log graph
3.6 Define the term: outgassing.
3.7 Identify materials that are the major sources of outgassing
in vacuum systems.
3.8 Describe the effects of outgassing and contamination on
vacuum system performance.
4.0 Low Vacuum Systems
4.1 Sketch and describe the mechanical operation of the following
mechanical pumps: rotary oil-sealed mechanical pump, dry pump,
and lobe pump.
4.2 Define the term: backstreaming.
4.3 List methods to eliminate or minimize backstreaming in
4.4 Give the operating pressure range and operating principle of
the following low-vacuum gauges: absolute pressure gauge,
diaphragm gauge, capacitance manometer, thermocouple gauge and
4.5 Describe how each low-vacuum gauge is maintained.
5.0 High Vacuum Systems
5.1 Sketch and describe the operation of the following high
vacuum pumps: turbomolecular pumps, cryo pumps, diffusion pumps,
cryo panels and cryo traps, and getters.
5.2 State the operating pressure range for each pump listed in
5.3 Given a specific gas, select the pump that would produce the
highest pumping speed.
5.4 Identify the components and describe the theory of operation
of the following high vacuum gauges: cold cathode ionization
gauge and hot cathode ionization gauge.
5.5 List the limiting factors for high and low pressure limits
for each type of gauge listed in Objective 5.4.
6.0 Leak Detection
6.1 Describe the liquid seal leak detection method.
6.2 Draw a block diagram of a leak detector indicating test
manifold, isolation valve, accumulator or throttle valve,
discharge gauge, mass spectrometer, roughing pump and high vacuum
6.3 Demonstrate troubleshooting skills by systematic leak
detection using helium gas.
6.4 Relate leak rate to standard cc/sec.
6.5 Define the term: virtual leak.
7.0 Residual Gas Analyzer
7.1 State the purpose of a residual gas analyzer.
7.2 Identify the major components of RGA's .
7.3 Describe the differences in mass filtering between a
quadrapole and a magnetic sector RGA.
7.4 Analyze a mass spectrum in a typical vacuum situation.
8.0 Vacuum Components and Materials
8.1 Describe the operating principle and best usable pressure
range of the following fittings: O-Ring, Conflat flange, K-flange,
8.2 Describe the operating principles and correct operation of
the following valves: Regulators, Nupro pneumatic, needle valve,
throttle value, swing gate, and sliding gate.
8.3 Describe basic lubrication processes, fluid rheology and
techniques for vacuum lubrication.
8.4 Describe vacuum sealing and joining techniques: welded and
brazed metal joints, metal, glass and ceramic joints, elastomer
and metal-sealed flanges, valves, and motion feedthroughs.