Oxford-100-Manual.pdf - 第279页
System Manual Oxford Instruments Plasma Technology All OIPT Systems (corresponding to RV101) to position 'a' and begin turning the potentiometers anti- clockwise again until the oscillations stop. 15) Confirm t…
All OIPT Systems
Oxford
Instruments
Plasma
Technology
System
Manual
10)
Manually
match
to
the
lowest
possible reflected
power
using
the
AMU
control
panel, and make sure a plasma
is
running.
Adjust
the
error
signal zero
potentiometers
RV1
and
RV2
(located on
the
same side
of
the
AMU
as
the
RF
in
connector;
see
Fig
1),
while
monitoring
the
two
error
signals on
JP3
pins 1 and 3
(See
Fig 6). These should be
less
than
20 mV
when
a match exists.
Amplified
error
signals
are accessible
at
TP
10 and
TP
110; these should be made
as
low
as
possible
when
the
RF
is
well
matched.
For
Vacuum
Capacitor
AMU
(AMU
board
REVOS
and
earlier):
If
it
is
not
possible
to
find
a match
position
due
to
the
match
position
being beyond
the
range
of
the
capacitors, stop
the
process and remove
the
AMU
cover again.
If
C1
is
attempting
to
drive
above
the
maximum position, add 180
pF
padding
capacitor
(Part
Number
94-ECC1218),
or
turn
2 turns anti-clockwise
towards
maximum.
If
C1
is
attempting
to
drive past
the
minimum
position, remove a
padding
capacitor
if
already
fitted,
otherwise
turn
2 turns clockwise
towards
minimum.
If
C2
attempts
to
drive above
the
maximum
position
turn
2 turns anti-clockwise,
if
C2
attempts
to
drive
below
the
minimum
position,
turn
2 turns clockwise.
Whilst
doing
this, be
careful
not
to
turn
the
capacitors beyond
their
physical end stops.
For
Vacuum
Capacitor
AMU
(AMU
board
with
capacitor
range
mod.):
If
C1
attempts
to
drive
above maximum position, add 180
pF
padding
capacitor.
If
C1
is
attempting
to
drive past
the
minimum
position, remove a
padding
capacitor
if
already
fitted.
If
C2
attempts
to
drive past
maximum
or
minimum
position, check
that
the
correct
inductor
is
fitted
and
that
the
capacitors are correctly
fitted
to
the
system.
If
these are correct,
the
match position
is
out
of
the
range
of
C2.
For
Air
Vane
Capacitor
AMU:
If
C1
or
C2
attempts
to
drive above
maximum
position, add 180
pF
padding
capacitor.
If
C1
or
C2
is
attempting
to
drive past
the
minimum
position, remove a
padding
capacitor
if
already
fitted.
It
is
not
necessary
to
reset
the
positions
of
the
Air
Vane Capacitors.
11) Increase
the
RF
power
in
a
few
steps
to
maximum
and check
for
RF
leakage, arcing
or
local overheating.
12) Rematch manually,
when
at
maximum
RF
power,
manually
to
less
than
1%
reflected
power
if
possible;
less
than
3%
is
the
maximum
reflected
power
acceptable. Refine
the
zero settings
of
the
error
signals.
13)
Make
a
note
of
the
capacitor position values
when
a
good
match
is
achieved. Stop
the
process and adjust
the
park
positions
to
a value
below
that
of
the
match position
(within
around
050 units
on
the
position display),
making
sure
that
C2
is
closer
to
its
match
position
than
C1.
Re-start
the
process
with
the
AMU
controller
in
auto
to
make sure
the
match
is
successful.
If
there
is
a large reflected
power,
repeat
Step 10.
If
there
is
a small
amount
of
reflected power,
which
can't
be reduced manually,
RV1
and
RV2
on
the
side
of
the
AMU
can be used
to
make
finer
adjustments
when
in
auto
mode.
14)
If
the
capacitors oscillate
when
in
auto,
reduce
the
gain
of
the
control
circuit by
slowly
turning
RV1
and
RV101
anti-clockwise
(if
C2
oscillates adjust
RV1,
if
C1
oscillates adjust RV101)
until
oscillations stop.
If
the
potentiometer's
RV1
or
RV101
begin
to
click
before
the
oscillations have ceased,
turn
them
fUlly clockwise
until
they
begin
to
click again and change
LK2
(corresponding
to
RV1)
or
LK102
Issue
6:
February 05
DIPT
Automatch
Unit
Page
12
of
20 Printed: 5-Jan-06, 8:03
System
Manual
Oxford
Instruments
Plasma Technology
All OIPT Systems
(corresponding
to
RV101)
to
position
'a'
and begin
turning
the
potentiometers
anti-
clockwise again
until
the
oscillations stop.
15)
Confirm
the
automatching
behaviour, increasing
the
RF
power
to
maximum in small
steps,
repeating
Steps 10
to
13
if
necessary.
4.
Operator
adjustment
WARNING
THE FOLLOWING ADJUSTMENT INVOLVES WORKING ON
THE
SYSTEM WITH
PANELS/COVERS REMOVED. IT SHOULD ONLY
BE
CARRIED OUT BY TRAINED
PERSONNEL
WHO
ARE AWARE
OF
THE
HAZARDS INVOLVED.
4.1
DC
bias I
Peak-to-peak
switch
setting
The DC bias /
Peak-to-peak
switch
is
located
on
the
outer
case
of
the
AMU,
adjacent
to
RV1
(null
adjustment
potentiometer).
See
Fig
1,
page
3.
This switch selects one
of
two
sensing
output
signals
from
the
AMU:
DC bias: This switch
setting
is
the
default
position. The
output
is
a
SCALED
dc
voltage
proportional
to
the
RF-induced self-bias on
the
electrode,
sometimes called
the
'DC
bias'. This
is
a negative
offset
voltage
on
the
electrode
with
respect
to
ground,
which
is
inverted and conventionally
referred
to
as
a positive value, typically 100 - 600 Vdc. Normal scaling can
read
up
to
1000 Vdc. This signal
is
read by
the
front-end
software
with
correct scaling
on
OIPT
tools.
Peak-to-peak:
The
output
is
an UNSCAlED dc
voltage
related
to
the
peak-to-peak value
of
the
RF
signal
at
the
output
of
the
automatch.
This can be useful
when
the
scaled dc bias
is
inaccessible,
for
example
if
the
electrode has
no
dc
contact
to
the
plasma because a
quartz
carrier
plate
masks
the
whole
electrode. The value displayed on
the
PC
screen
will
be an
arbitrary
value,
not
a
true
peak-to-peak value,
but
can still
be
a useful
monitor.
Note
that
the
software
has
no
knowledge
of
the
switch
setting
and
is
scaled
only
for
the
dc
bias setting.
5.
Operation
If
the
automatch
has been set
to
'auto',
the
unit
will
attempt
to
reduce
the
reflected
RF
power
to
minimum
without
the
need
for
operator
adjustments.
It
will
normally
reduce
reflected
power
to
less
than
2%
of
forward
power.
Use
manual
matching
for
the
following:
a)
One
or
both
capacitors has driven
to
a
limit.
b) To discover
if
a match exists
within
the
range
of
the
matching
unit.
The
adjustment
panel
for
the
automatch
is
located
behind
a
hinged
cover. Opening
the
cover
reveals
the
following
controls and indicators:
Printed: 5-Jan-06. 8:03
OIPT
Automatch
Unit
Page 13
of
20
Issue
6:
February 05
All
OIPT Systems
Oxford
Instruments
Plasma
Technology
System
Manual
Auto/manual
switch: In
the
'Auto'
position,
the
unit
will
attempt
to
tune
for
minimum
reflected
RF
power. In
the
'Manual'
position,
the
capacitors
positions are
controlled
manually.
C1
max/min switch: In manual mode, this switch can be used
to
drive
capacitor
C1
towards
maximum
or
minimum.
C2
max/min switch: In manual mode, this switch can be used
to
drive
capacitor
C2
towards
maximum
or
minimum.
Note
that
capacitor positions are displayed
as
a
three-digit
number
from
000 (minimum)
to
999 (maximum).
Display Selector
Switch:
C1
park.
Potentiometer:
C2
park.
Potentiometer:
The
RF
monitoring
positions display
the
analogue
voltages
on
the
remote
control
lines
to
the
RF
generators,
as
a service aid. The
Hillo
position reads a
high
(>9V) value
when
the
wafer
bias
RF
supply
is
at
full
scale, and a
low
«1V)
value
when
this supply
is
scaled back
to
one-
tenth
full
power. This
feature
improves resolution
of
RF
low
power.
This
control
can be
fitted
either
to
the
control
panel
or
on
the
AMU
control
board. The
automatch
will
drive
C1
to
this pre-set position
when
the
RF
is
turned
off,
if
the
unit
is
set
to
'auto'
This
control
can be
fitted
either
to
the
control
panel
or
on
the
AMU
control
board. The
automatch
will
drive
C2
to
this pre-set
position
when
the
RF
is
turned
off,
if
the
unit
is
set
to
'auto'
Issue
6:
February
05
DIPT
Automatch
Unit
Page 14
of
20
Printed: 5-Jan-06. 8:03