Utah-94-721002-System-Manual.pdf - 第137页

System Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~ =qÉÅÜåçäçÖó== mä~ëã~ä~Ä póëíÉãNMM WARNING BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY . j) If it should become necessa ry to change from PFPE to…

mä~ëã~ä~ÄpóëíÉãNMM lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual

WARNING

BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY.

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CAUTION

When changing or topping-up the lubricating oil in a pump, always use oil of the

same brand and type. If a change of brand or type is contemplated, refer to

Oxford Instruments Plasma Technology for advice.

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The lubricating oils used for pumps where the oil comes into contact with the pumped gases,

i.e. oil-sealed pumps such as rotary vane types, should be chosen to meet the specific

characteristics necessary for the process involved.

The vapour pressure must be low at the temperatures reached at the rubbing surfaces.

Viscosity should not vary significantly over the temperature range involved, and the water

absorption rate and content must be low.

Lubricating oils generally fall into one of two categories: mineral (hydrocarbon) based oil or

synthetic oil such as perfluorinated polyether. The synthetic oils are normally used where they

come into contact with strong oxidants such as nitrogen dioxide, oxygen, or one of the

halogens.

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Perfluorised polyether (PFPE) lubricants have the following properties:

a) They are stable up to 350

C, i.e. they do not decompose below this temperature.

b) They are chemically inert. They will, however, react with Lewis acids (BCl

, AlCl

etc.)

at temperatures over 100

c) They do not polymerise under the impact of high-energy radiation.

d) Since they tend not to keep contaminants suspended, pumps using these lubricants

must always be fitted with suitable oil filters.

e) They do not 'age' and therefore, if used correctly, need not be replaced during the

lifetime of the pump.

f) Any contaminants in the lubricant may be removed by fitting clean filters and

letting the pump run for several hours with inert gas ballast, the intake port having

been closed.

g) They do not protect metal surfaces against corrosion. Pumps should therefore always

be flushed with inert gas. Pumps using PFPE should be allowed to run continuously.

h) PFPE is incompatible with hydrocarbon oils, i.e. mineral oils, conventional greases

and cleaning agents.

i) If a pump uses PFPE lubricant only Freon 113 or Frigen 113 may be used as a cleaning

agent, and only PFPE grease may be employed.

Maintenance

UC Davis 94-721001 Issue 1: March 06 Page 6-18 of 22 Printed: 22-Mar-06, 7:41

System Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== mä~ëã~ä~ÄpóëíÉãNMM

WARNING

BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY.

j) If it should become necessary to change from PFPE to mineral oil lubrication or vice

versa, the pump must be completely disassembled, freed of lubricant and fitted with

new gaskets and vanes.

k) At temperatures over 350

C, hazardous gaseous decomposition products are

formed. Therefore do not smoke in rooms where PFPE is used, and make sure that

no tobacco comes into contact with PFPE.

l) When handling PFPE, protective clothing must be used.

m) Do not mix PFPE with used oil. Dispose of them separately.

n) PFPE is normally odourless and colourless. Cloudiness or odour is a sign of

contamination.

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Where mineral oils are used, the rate of oil deterioration for a particular pump and process

should be established at an early stage, and oil changes based upon this information.

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Before carrying out a process, in the process chamber on a wafer which is a different size to

that last processed, it is necessary to fit the correct type of clamping plate. Clamping plates

are available for various sized wafers.

To change the clamping plate, use the following procedure (refer to Fig 6.1, page 6-20):

6) If necessary, vent the process chamber.

7) Open the process chamber lid.

8) Wearing powder-free gloves, unscrew the three clamping plate securing screws then

remove the clamping plate from the process chamber and place on a clean surface.

9) Take the replacement clamping plate and mount it on the three supporting pillars

then insert and tighten the three securing screws.

10) Close the process chamber lid.

Maintenance

Printed: 22-Mar-06, 7:41 Page 6-19 of 22 UC Davis 94-721001 Issue 1: March 06

mä~ëã~ä~ÄpóëíÉãNMM lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual

WARNING

BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY.

THERMOCOUPLE

CHAMBER

BASE

WAFER

CLAMP

TABLE

DARK SPACE

SHIELD

TABLE SUPPORT

TUBE

O RING

PUMPDOWN

PIPE FLANGE

FEEDTHROUGH

COMPONENTS

STAINLESS

STEEL

BELLOWS

SPRING

COMPRESSED

AIR CYLINDER

COMPRESSED

AIR CYLINDER

(ONE EACH SIDE

OF CLAMPING

PLATE)

WAFER

LIFT

ASSEMBLY

(FITS INSIDE

TABLE SUPPORT

TUBE)

Clamping

plate

Clamping

ring

Setscrew &

compression

spring (3-off

on each side

of clamping

ring)

3-pin wafer

support

Quartz

insert

SAFETY RELIEF

VALVE

CONTROL VALVE

LIQUID NITROGEN

OUT

HELIUM IN

Fig 6.1: 94-100-5-12A Cryo / heated -150 / 400C He lower electrode

Maintenance

UC Davis 94-721001 Issue 1: March 06 Page 6-20 of 22 Printed: 22-Mar-06, 7:41