Utah-94-721002-System-Manual.pdf - 第232页

lfmq=póëíÉãë lñÑç êÇ=fåë íêìãÉåí ë=m ä~ë ã~=qÉÅÜåçäçÖó== System Manual SK= mêçÅÉëë=Ö~ëÉë= REGULA TOR 0.5 BAR T O 5 BAR (7 TO 75 P SIG) LO CA T ED ADJACENT TO THE SYSTEM SUPPL Y TO GAS POD OR INTERNAL GAS LIN E MINI MUM P…

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Nitrogen is required to vent and purge process chambers, load locks and pumps.

2 MICRON

FILTER

REGULATOR

1/4"

SWAGELOK

CONNECTOR

TO PLASMALAB

OR IONFAB

SYSTEM

TO PUMP

PURGE

CONNECTOR

0 TO 1 SLM

FLOW CONTROL

ROTAMETER

(IF REQUIRED)

Fig 5.1: Recommended nitrogen supply installation

Semiconductor grade fittings and pressure regulators, together with electropolished stainless

steel tube must be used to ensure that gas quality is not degraded. Purges to turbo pumps are

supplied by OIPT as part of the system. The customer will usually need to fit a purge to the

rotary pump. See below.

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• Pipework fittings and

pressure regulators:

Semiconductor grade

• Gas handling tubing: Electropolished stainless steel

• Purity: At least 99.99% or higher to satisfy process

requirements.

• Filtration: 2 micron filter mounted adjacent to the

system.

• Regulation: 0.5 to 5 bar (7.5 to 75 psig)

• Minimum pressure at input

to system:

3 bar (45 psig). Certain pumps, for example

Edwards Drystar pumps, may need up to 5 bar

(75psig) to ensure satisfactory purging. Check

with the vendor's instructions.

• Rotary pump purging

It is the customer’s responsibility to ensure that a rotary pump purge

connection is fitted and used correctly. This is needed to ensure the protection

of the pumping system from the customer’s process, and may also be required

by local safety regulations. Because customers’ requirements vary, components

are not supplied automatically by OIPT. Kits of parts are available if required.

Contact OIPT for further information.

It may be safe to omit this feature on certain systems, such as Ionfab machines

running inert gas processes. However, unless the customer has written

agreement on this point from OIPT, any damage caused by the omission cannot

be covered by the system warranty.

Services Specifications

Printed: 6-Jan-06, 8:44 Page 13 of 22 Issue 16: April 05

lfmq=póëíÉãë lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual

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REGULATOR 0.5 BAR TO 5 BAR

(7 TO 75 PSIG) LOCATED

ADJACENT TO THE SYSTEM

SUPPLY TO

GAS POD

OR INTERNAL

GAS LINE

MINIMUM PRESSURE

3 BAR (45 PSIG)

ALL FITTINGS,

REGULATOR AND

FILTER TO BE

SEMICONDUCTOR

GRADE

LL TUBING TO BE

ELECTROPOLISHED

STAINLESS STEEL

NOTES:

Fig 6.1: Recommended process gas supply installation

Semiconductor grade fittings and pressure regulators, together with electropolished stainless

steel tube must be used to ensure that gas quality is not degraded.

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• Pipework fittings and pressure

regulators:

Semiconductor grade

• Gas handling tubing: Electropolished stainless steel

• Purity: At least 99.99% or higher to satisfy

process requirements.

• Filtration: A 2-micron filter is fitted to each

gas line supplied as part of the

system. For other grades of filter,

please consult OIPT.

• Regulation: 0.5 to 5 bar (7.5 to 75 psig)

• Minimum pressure at input to system: 2 bar (30 psig)

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The specifications for the Helium gas supply are as for those of the process gases given in sub-

sections 6 and 6.1 with the exception that the maximum pressure at the inlet to the

pressure controller must not exceed 3.5 bar (43 psig). The design of the Helium

pressure controller is such that it can be destroyed by higher pressures.

Services Specifications

Issue 16: April 05 Page 14 of 22 Printed: 6-Jan-06, 8:44

System Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== lfmq=póëíÉãë

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The low vapour pressure can lead to condensation in the gas supply lines, particularly at cold

points or when the gas passes into a cooler region. This condensation can result in a build up

of liquid in the gas pipe, usually at the low points or u-bends in the gas line, often leading to

instability of gas flow, especially if liquid condenses or flows into the MFC.

The low vapour pressure can also result in very low gas pressure if the gas cylinder is very

cold, e.g. if it is kept outdoors in the winter.

Therefore, it is important to adhere to the following guidelines:

(A) It is necessary to keep the gas cylinder indoors (in an extracted gas cabinet) to avoid

loss of line pressure when the outside temperature is cold.

However, do

NOT heat the gas cylinder with a heated jacket as this can cause

condensation problems when the gas passes into the cooler gas lines. Room

temperature is warm enough to provide sufficient vapour pressure.

(B) It is important to maintain a positive temperature gradient from the cylinder to the

MFC, or at least keep them at the same temperature. The simplest method is to

position the gas cabinet close to the gas pod, minimising the chances of temperature

differences, reducing the length of the gas pipe, and hence minimising the chances

of condensation. If this is not possible, then it is necessary to heat the gas lines by

the use of heater tape.

The MFC will also need to be heated. OIPT offers a heated MFC kit for these gases.

Alternatively, heater tape can be wrapped around the MFC. However, in this case, it

may also be necessary to detach the MFC from the backing plate to avoid heat loss

through the plate, and to cover the MFC in insulation material to avoid cooling from

air flow within the gas pod (from the gas pod exhaust).

It will then be necessary to set the MFC temperature hotter than the gas line

temperature, which in turn is hotter than the gas cylinder temperature. A typical set-

up might be MFC 40 °C or above, gas line 30-40 °C, and gas cylinder at room

temperature.

lines completely, and optimise the heater tape arrangement and temperature

setpoints before refilling the gas line.

(D) For SiCl

it is important to use a dedicated SiCl

MFC as this is designed specifically for

low-pressure condensable SiCl

operation.

Services Specifications

Printed: 6-Jan-06, 8:44 Page 15 of 22 Issue 16: April 05