Start
the grey pump in the service corridor behind the aligner
Open
the valve for the Nitrogen gas
Plug
in the power for the air conditioning and HEPA filter unit
In
the "Turn Table" group put the switches in "single" and "cylinder work"
positions.
in
the "shutter release control" group put the switches in "non release" and
"with alignment" positions
In
the exposure group put thee switch in "manual off" position.
Plug
in the power cord for the PPC and power supplies
Start
the PPC by pushing the "power" button
Turn
on the power supply for the mercury lamp
Press
the "start" button on the mercury lamp power supply and hold it for 1-3
seconds (you should hear a sharp sound from the power supply)
Wait
for 30-40 minutes for the mercury lamp to warm up.
Exposing:
Turn
on the power for the yellow alignment light.
Place
your mask in the mask holder and turn on mask vacuum
Put
your sample in the center of the sample holder
Press
the "start" button to rotate the stage, the expose indicator should now be on.
Remove any previously exposed samples.
Move
the "wafer focus" to zero position
Focus
on your sample
Focus
the mask on your sample using the "mask focus"
Make
a rough alignment of your pattern
Move
"wafer focus" to the 100 µm position
Align your
sample
Set the
exposure time on the timer using the outer scale
Flip the
switch for release to "automatic release" position.
Move the
microscope to the left edge to start exposure.
If you have
more samples to expose, return to point 3
Flip the Turn
table switch to "Cylinder no work" position
Flip to release
switch to "non release" position
Press the
"Start" button to rotate the stage.
Remove your
sample
Put the
microscope back in a centered position
Turn off the
alignment lamp.
When exposing
next sample start from 1
Open
for mask loading,
press button at upper left corner to open.
Mask
loaded
Focus knob
Optical column with mask
and wafer focus
System shut down:
Turn
of the vacuum for the mask and remove the mask
Move
the microscope to a centered position if this is not already done. Not doing
this can damage the "automatic release" mechanism that starts the exposure.
Place
the silicon wafer on the mask holder to prevent dust from falling into the
optical column.
Turn
of the yellow alignment light if this is not already done
Turn
of the mercury lamp power supply
Turn
of the power for the PPC
Unplug
the power cords for the power supplies and the PPC.
Wait
for 30 min and then turn of the nitrogen flow and the grey pump in the service
corridor.
Unplug
the air conditioning/HEPA unit.
General information and operating tips
If you can't focus on your sample (i.e. it is too low or too
high) you can slowly turn the "Pressure" valve on the right side of the PPC to
raise and lower the stage. If the stage doesn't move, reduce the pressure to
minimum and slowly start to increase it. At some point the sample holder will
start to move up and down in a pulsing movement, this indicates that the
pressure is just below the lower threshold. By slowly increasing the pressure
from this point you should be able to move the stage. Please do note that the
pressure and position of the stage also has an upper limit.
Side Panel with
pressure control
In "cylinder no work" mode the stage can be rotate time and
again but it will not raise the stage and it will not be possible to start an
exposure, this mode is good for unloading the last sample in a series.
In "Cylinder work" mode the stage can only be rotated once
and then the PPC will go into exposure mode. If you don't want to expose for
some reason but want to rotate the stage to remove your sample press the "Stop"
button once to enter emergency stop mode and end the expose mode, then press it
again to end the emergency stop mode.
In "non release" mode the system will not start an exposure
if the microscope is moved to the left edge; this can be good while aligning so
you don't accidentally start an exposure while looking into the microscope.
In "automatic release mode" the system will start the
exposure when the microscope reaches the left edge; this is how you normally
start the exposure.
When you move the "wafer focus" you will also lose some fine
alignment, therefore always do your fine alignment after using the "wafer
focus". Not using the "wafer focus" will result in poor resolution. This has no
effect if your smallest structure is 20 or so microns, but it is necessary to
achieve higher resolution.
The mercury lamp of the aligner only generates a uniform
dosage in the central part of the sample holder make sure this is where your
pattern is.
If your mask is much bigger than the holder and you worry
about scratching patterns on the edge there is a piece of clean room paper cut
so that it will cover the edge of the holder to prevent scratching.
Don't forget to cover the column when turning of system or
the optical part will get dirty.
Don't forget to unplug the cables or some of the
transformers and power stabilizers will overheat.
Please turn of the yellow light while not aligning since
this generates quite a lot of heat and don't need to heat up before use.
Let the mercury lamp cool down before turning of the pump,
this will greatly increase its life time.
If you accidentally turn of the mercury lamp let if cool
down for at least 40 minutes before turning it back on, otherwise it could be
damaged or explode and the resulting mercury fumes are very toxic.
Check if someone else wants to use the system after you
before turning of the mercury lamp.
If leaving for lunch leave the mercury lamp on, it takes
more damage from being turned on then from running for one hour. If leaving for a
longer period of time, turn it of, it has a limited life time (1000 hours or
so).
If you notice that the exposure times start to increase a
lot (3-5 times longer than usual), call someone who is responsible for the
system, the mercury lamp might be getting old and has to be changed or it might
just be out of alignment. If the lamp is getting old the risk of explosion increases.