Oxford-100-Manual.pdf - 第51页

System Manual Oxford Instruments Plasma Technology Plasma lab System 100 GAS POD PCB CONTROL CABLE FROM PLC IPCB \ SIX-WAYSMC ASSEMBLY GAS POD COVER INTERLOCK MICROSWITCH 100MM EXTRACTION COLLAR PROCESS GAS OUT TO CHAMBE…

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Plasmalab
System
100
Oxford
Instruments
Plasma
Technology
System
Manual
3.9
Gas
handling
system
WARNING
CONTACT WITH TOXIC GASES CAN CAUSE DEATH OR SERIOUS INJURY.
USERS SHOULD PERFORM THEIR
OWN
RISK ASSESSMENT
OF
HAZARDOUS GASES
TO
BE
USED
ON
THE SYSTEM.
BEFORE VENTING THE PROCESS CHAMBER, ALWAYS ENSURE THAT THE SYSTEM IS
ADEQUATELY PURGED
AND
PUMPED;
SEE
'VENTING
THE
SYSTEM' IN SECTION 5
OF
THIS
MANUAL.
3.9.1
94-81-9-51/8
Gas
pod
(PLC
version)
The purpose
of
the
gas
pod
is
to
feed a
mixture
of
process
gases,
at
specified
flow
rates,
to
the
process chamber. Selection
of
gases and
flow
rates are
determined
by
the
system
controller.
A 'clean gas'
line
can
be
incorporated
to
feed an etch gas
mixture
into
the
process
chamber
to
remove process residues.
The gas pod, shown
in
Fig 3.5, comprises a steel
case
with
a removable cover.
An
extraction
collar
at
the
top
of
the
case
enables any leaked gas
to
be safely removed by a
laboratory
extraction
system. The back panel
of
the
case
is
fitted
with
fixing
holes
for
wall
or
frame
mounting.
UC
Davis 94-721001
Issue
1:
March 06
Description
Page 3-14
of
22
Printed: 22-Mar-06, 7:29
System
Manual
Oxford
Instruments
Plasma
Technology
Plasma
lab
System 100
GAS POD
PCB
CONTROL
CABLE
FROM
PLC
IPCB
\
SIX-WAYSMC
ASSEMBLY
GAS POD COVER
INTERLOCK MICROSWITCH
100MM EXTRACTION
COLLAR
PROCESS GAS
OUT
TO
CHAMBER
'CLEAN
GAS'
LINE
Fig 3.5: 94-81-9-51 Gas
pod
The
case
incorporates stations
for
up
to
six gas lines. The
outputs
from
the
gas lines are fed
into
a
common
manifold
which
is
connected
to
the
process chamber gas line. Pneumatically
operated
shut-off
valves
in
each gas
line
are driven
by
associated
SMC
valves,
powered
by
compressed
air
and
controlled
by
signals
from
the
system
controller.
A separate
SMC
valve,
controlled
by
an
interlock
microswitch, prevents
the
opening
of
any gas
shut-off
valve
when
the
case
cover
is
not
fitted,
or
when
either
of
the
system
interlock
lines are open.
The
Gas
Pod
PCB
receives signals
from
the
system
controller,
to
control
the
SMC
valves, and
the
Mass Flow Controllers (MFC)
fitted
in
the
gas lines. For a circuit
diagram
of
the
Gas
Pod
PCB,
refer
to
drawing
SE81
015942 in
Volume
2
of
this manual.
The 'clean gas'
line
flow
rate
can be set
either
manually
by a variable valve
(as
shown in Fig
3.5)
or
by
an
MFC.
Note
that
the
'clean gas'
is
usually supplied
from
a cylinder
containing
the
required
gas
mixture.
An
alternative
method
is
to
mix separate gases
in
optional
additional
gas lines.
Printed: 22-Mar-06, 7:29
Description
Page 3-15
of
22
UC
Davis 94-721001
Issue
1: March 06
Plasma
lab
System
100
Oxford
Instruments
Plasma
Technology
WARNING
System
Manual
3.9.2
THE CONNECTION FROM THE GAS POD
MANIFOLD
TO
THE
PROCESS
CHAMBER
SHOULD NOT INCLUDE
ANY
SHUT
OFF
VALVE, UNLESS THIS HAS BEEN CLEARED
WITH OXFORD
PLASMA
TECHNOLOGY. A BLOCKAGE
HERE
COULD CAUSE
PROCESS
GASES TO
MIX
AND
CROSS CONTAMINATE IN THE HIGH
PRESSURE
GAS DELIVERY
PIPEWORK.
94-81-9-11
Standard
non-toxic
gas
line
The standard
non-toxic
gas line
is
shown in Fig 3.6.
All
gas
fittings
are
VCR
and all stainless
steel
pipework
connections are
welded.
The 'gas
in'
tube
passes
into
the
side
of
the
case,
protected
by a
grommet.
A
ferrite
core,
fitted
to
the
'gas
in'
tube, reduces
the
susceptibility
of
the
gas
pod
electronics
to
signals
from
nearby
transmitting
devices, e.g.
mobile
phones,
modems, etc
..
Gas
from
the
customer's
cylinder/regulator/filter
flows
into
the
gas in
tube
to
the
filter.
The gas
flows
through
the
2-lJm
filter
to
the
mass
flow
controller
(MFC).
The
MFC
controls
the
flow
of
gas
as
commanded
by
the
system controller. The gas
then
flows
through
the
pneumatically
controlled
outlet
shut-off
valve and
into
the
gas
out
manifold
where
it
is
mixed
with
the
other
process gases
before
flowing
into
the
process chamber.
WARNING
THE CLOSED INLET VALVE REMAINS SHUT FOR DIFFERENTIAL
PRESSURE
UP TO 5
BAR. A FAILURE UPSTREAM WHICH PRODUCES LINE
PRESSURES
ABOVE THIS WILL
NOT
BE
CONTAINED. IF THIS PRODUCES A HAZARD, THE CUSTOMER IS WARNED TO
FIT
ADDITIONAL
PROTECTION UPSTREAM.
OUTLET SHUT-OFF
VALVE
(PNEUMATICALLY
CONTROLLED)
~
MASS
~
FLOW
~
CONTROLLER
2
....
m FILTER
.....,""'~
........
~
~
~
GAS LINE EXTENSION
~
~FERRITE
CORE
~
~
GROMMET
GAS
IN
TUBE
(STAINLESS STEEL)
Fig 3.6: 94-81-9-11 Standard non-toxicgas lines
UC
Davis 94-721001
Issue
1:
March 06
Description
Page 3-16
of
22
Printed: 22-Mar-06. 7:29