Utah-94-721002-System-Manual.pdf - 第168页

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AMU Abbreviation for Automatch Unit. This is a self-controlling variable capacitor,

which is connected between an electrode (to which it is normally close-coupled)

and the discharge power supply. Its purpose is to shift the voltage and current

waveforms to maximise the power transfer. It also transforms the load

impedance to 50Ω.

APC Abbreviation for Automatic Pressure Controller. Refers to a variable

conductance valve, which, under the control of a closed loop feedback system,

controls the chamber pressure. The controller is a remote electronic module

with inputs from a chamber pressure gauge, and from the system master

controller.

Backing pump A pump in series with, and downstream of, the main high vacuum pump. (See

also Rotary pump)

Backing valve The valve which, when open, allows the backing pump to pump gas from the

main pump.

Baratron

See CM gauge. Baratron is a trade name.

Base pressure The lowest pressure attainable by a high vacuum pump. Alternatively, the

pressure, which should be attained before starting a process.

Bayard-Alpert gauge See Ion gauge

Clean gas This refers, in fact, to 'cleaning gas'. It is a gas which, when converted to a

plasma, removes contamination from the walls of the chamber and from the

electrodes.

Cluster An array of processing chambers around a single load lock chamber housing a

substrate-handling robot.

CM gauge (Baratron) Capacitance manometer gauge in which gas pressure deflects a membrane and

thus a measured capacitance. Measures absolute pressure down to

approximately 10

-5

Torr. Not affected by corrosive gases. Does not need a

correction factor for different types of gas.

Cryo pump (Meissner

coil)

These pumps trap gas on a very cold surface. They usually consist of a closed

circuit helium refrigeration system. They require periodic regeneration, during

which they cannot be used for pumping. Base pressure approximately 10

-9

Torr.

Driven electrode The electrode to which the electrical discharge power is applied. The other

electrode may be either earthed or at floating potential.

DSµW An abbreviation for the Downstream Microwave process.

ECR An abbreviation for the Electron Cyclotron Resonance process.

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Electrode One of two metal plates within the process chamber, which form part of the

electrical discharge system. The lower electrode is sometimes referred to as the

'table'. They are fabricated from aluminium alloy or stainless steel, and may

either be heated by integral electrical resistance elements, or cooled by chilled

water pipes.

Foreline The line immediately downstream of the high-vacuum pump (see Roughing

line).

Foreline pump See Rotary pump

Gas ballast Inert gas introduced into a port on a rotary pump to improve its ability to pump

condensable vapours.

Gas factor Ion gauges, Pirani gauges, Penning gauges and mass flow controllers need to be

adjusted when run on different gases, to prevent them from being inaccurate.

This 'gas factor' depends on the gas and also the type of instrument.

Gate valve A high vacuum valve with a stainless steel shutter having linear motion. It may

be used for high vacuum isolation and also for pressure control.

Hivac valve

(High vacuum valve)

The valve which isolates the turbo / cryo pump from the process chamber.

HPN An abbreviation for ‘High Power Neutralizer’; the name the Oxford Instruments

Plasma Technology gives to their ion beam neutralizer.

ICP An abbreviation for Induction Coupled Plasma.

Interlock A safety device (either software or electrically implemented) that allows a piece

of apparatus to function only when predetermined conditions are fulfilled.

Ion beam system This uses an ion source in a vacuum chamber to direct a flux of energetic ions at

a substrate in order to etch the surface or uses the ion source to sputter from a

target to deposit material on to the substrate.

Ion gauge

(Bayard-Alpert gauge)

This gauge uses a glowing cathode to emit electrons. Any positive ions created

by collisions with gas molecules are collected on a thin central ion collection

wire. The ion current varies with the gas density. Used for checking very low

base pressures down to 10

-10

Torr. It needs to be calibrated to the gases being

measured (see Gas factor). The filament lifetime will be limited in reactive gases.

Leak up rate The rate of increase of pressure, due to leakage and outgassing, in a sealed

chamber, which has been pumped down to base pressure.

Load lock A sealable chamber adjacent to the processing chamber, which allows the

specimen to be loaded onto the substrate table without having to vent the

processing chamber.

Meissner coil See Cryo pump

MFC Short for mass flow controller. This is a closed loop device, which controls the

flow rate of piped gases under the control of an analogue signal. It also outputs

a measured flow rate analogue signal. It needs to be calibrated to the gases

being controlled (see Gas factor).

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Micron

Unit of pressure; 10

-3

Torr. Equivalent to the pressure required to support a

column of mercury one micron (length) high.

Micron

Unit of length; 10

-6

metres.

Millibar Unit of pressure; 1/1000 of one atmosphere or bar.

Nupro valve Nupro is a manufacturer of commonly used pneumatically operated gas line

valves.

Outgassing The vaporisation of contaminants from the surfaces of the components exposed

to the vacuum.

PE An abbreviation for the Plasma Etch process.

PECVD An abbreviation for the Plasma Enhanced Chemical Vapour Deposition process.

Penning gauge This gauge uses a glow discharge between electrodes and a permanent

magnetic field. The ion current varies with the gas density. Used for checking

base pressures down to 10

-8

Torr. It needs to be calibrated to the gases being

measured (see Gas factor).

PFPE An abbreviation for perfluorised polyether lubricating fluid. This synthetic

lubricant is used in a highly oxidising environment where mineral (hydrocarbon)

oils would deteriorate too rapidly.

Pirani gauge Senses the thermal conductivity and hence the pressure of a gas by the power

required to maintain the temperature of a warm filament. Used to monitor

roughing pump pressures down to approximately 10

-3

Torr. It needs to be

calibrated to the gases being measured (see Gas factor).

Plasma A region of electrons, positive ions and neutral gas particles created between

electrodes within which the various etching or deposition processes take place.

Plasma system This generates a plasma above a substrate in a vacuum chamber and uses the

action of the plasma to etch from, or deposit material onto, a substrate.

Platen The plate, which supports the substrate to be processed.

RF An abbreviation for Radio Frequency, often 13.56 MHz.

RIE An abbreviation for the Reactive Ion Etching process.

Roots pump (blower) A pump having rotating lobes, which intermesh to give a positive displacement

of the pumped gas. The parts of the pump exposed to the pumped gas are

usually self-lubricating, i.e. lubricating fluids are unnecessary. Approximate base

pressure 1 mTorr.

Rotary pump (backing

pump, roughing

pump, foreline pump)

Short for Rotary Vane Pump, this consisting of an eccentrically mounted shaft

carrying spring-loaded vanes rotating within a cylinder. The vanes are oil sealed.

The choice of lubricant depends upon the process. Approximate base pressure

40 mTorr (single stage), 1 mTorr (two stage).

Roughing line The line between the roughing pump and the chamber.

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