INTRODUCTION:
The spinner is a fairly sophisticated tool with precise control of: 1) spin speed and acceleration, 2) exhaust during spinning which controls drying rate and can improve film quality, and 3) number of steps in the spin cycle. At the same time it is a delicate instrument which can easily be damaged. It also has the potential to be dangerous when used improperly since it spins at high RPMs and can throw a substrate off the chuck making sharp high speed projectile.
SAFETY:
Saftey goggles must be worn throughout the spin coat procedure by all people in the clean room or in the vicinity of any spinner. It is the responsibility of the person using the spinner to assure all others are wearing proper eye protection. The samples rotate at very high velocities (several thousand RPM), and it is imperative to close the spinner lid during this operation. The Brewer system is interlocked, but others are not.
The Brewer system is mounted on a bench and is continuously exhausted to minimize exposure to photoresist fumes. You must, however, put the photoresist on your wafers. The best procedure is to open the photoresist container in the fume hood and insert one of the laboratory pippettes used to dispense photoresist into the container. Next open the spinner lid and hold the photoresist container above the spinner (so most of the fumes will be collected by the exhaust connected to the spinner bowl) while dispensing resist onto your sample. Immediately move the photoresist back to the hood and close the spinner lid.
CHUCK INSTALLATION:
Proper installation and maintenence of spinner chucks is critical to avoiding damage to the tool. Several chuck sizes are available. You should choose the largest one which is at least 1/2" smaller then the minimum diameter of your sample. If the chuck is too large, some of the vacuum surface may become exposed allowing photoresist to be collected by the vacuum line. One resist gets on the chuck or in the vacuum line, it can thicken, freezing the chuck onto the spindle. A hard pull to remove the chuck can damage the bearings. Similarly, if solvent is used to loosen the chuck it will transport down the spindle and again attack the bearings. NEVER TRY TO FLUSH THE SPINDLE WITH SOLVENT UNDER ANY CONDITION, you will damage the instrument.
Once you have selected a chuck, place it on the spindle rotating so the key in the spindle engages the slot in the chuck. Now insert and tighten the screw that holds the chuck to the spindle shaft (for the smallest chucks the screw is not used). This screw has a through hole for vacuum. The screw does not need to be real tight. The system is now ready to be used. When you finish using the system, remove the screw and the chuck. As long as you do this right away, the chuck should not become frozen to the spindle. If it does, don't try to force it, rather, report this to the lab coordinator. Once the chuck is removed you should remove any photoresist residue from the chuck and spindle. In the case of the spindle this should be done with a Kimwipe dampened with acetone. Make sure it is only damp so acetone does not transport down the spindle to the bearings.
PROGRAMMING:
These instructions are for programming a two step process using typical spin speeds and accelerations for the processing course. If you want something more sophisticated you should consult the manual.
1) Turn on the instrument. The front panel display will read CEE--100 Auto
Disp.
2) Press the PROG key, the display will read "PROG MODE/PROG/#?x"
where x is a number corresponding to the last program accessed. To edit a program,
press the number of the program and then ENTER. Values from 0 to 9 are acceptable
for program number, but it is probably best to use program 1 unless you want
to save a particular program since 1 is generically used by the processing class.
If you use one of the others, without asking permission, you may erase someone's
program. In any case, no matter what number you use, its possible your program
could be altered by another user, so its best to record the values you are using.
For the rest of this example, I will assume its program 1.
3) After hitting ENTER, the display will read DISPENSE 1=ON 0=OFF. You should
depress 0 and hit ENTER since we do not have an autodispense feature on our
unit. If 0 is the prior value, you can just hit ENTER.
3) The display will now read "PG/1 VEL/0 yyyyRPM." This is telling
you that you are setting the 0th velocity step of program 1 and that the previous
speed was yyyy. Press the digits for the desired spin speed in RPM (500 in this
case) and then ENTER.
4) The display will read "PG/1 RMP/0 yyyy R/S." This is telling you
to set the 0th ramp in program 1 and that it was previously set to yyyy RPM/second.
Now enter the acceleration for the first spin cycle which is typically 100RPM/second
and hit ENTER. Note, on any of these steps if the right value is already displayed
you can just hit ENTER without entering a number first.
5) The display now reads "PG/1 TIME/0 y SEC," where y is the previous
spin time for the 0th step. Enter the spin time you want, typically 9 seconds,
and hit ENTER.
6) The display now reads "PG/1 EXH/0 y." This is to set the exhaust
during the 0th spin cycle where 0 is no exhaust and 1 is exhaust full on. For
typical use, depress 1 and hit ENTER.
7) The display reads "PG/1 VEL/1 yyyyRPM. You are now beginning the process
of setting up the 1th spin step. As above, you put in the value of velocity
you would like in place of yyyy and hit ENTER or if yyyy is the value you want,
just hit ENTER.
8) The display will read "PG/1 RMP/1 yyyy R/S." Enter the acceleration
for the second spin cycle (the 1th cycle) which is typically 1000RPM/second
and hit ENTER.
9) The display now reads "PG/1 TIME/1 y SEC." Enter the spin time
for the 1th step, typically 40 seconds, and hit ENTER.
10) The display now reads "PG/1 EXH/1 y." For typical use, depress
1 and hit ENTER.
11) The display now reads "PG/1 VEL/2 yyyy RMP. Typically yyyy will be
the letters END. Then you just hit ENTER and the program is complete. The display
returns to CEE--100 Auto Disp. If something other then END is written here,
press CLEAR and then ENTER and it will end the program. If you wished to have
more spin steps, it is at this point that you would enter a new spin speed instead
of END, with subsequent entries allowing the ramp, exhaust etc. to be set.
OPERATION:
1) Make sure the vacuum pump power switch is on. The power switch is located
on the power cord of the vacuum pump. Center your wafer on the vacuum chuck.
CLOSE THE LID AND MAKE SURE EVERYONE IS WEARING SAFETY GOGGLES.
2) The display should read CEE--100 Auto Disp. Press the RUN key.
3) The display reads "RUN PROG#?_". The cursor will flash indicating
you need to put in a run number. Press the program number you want to run and
then ENTER.
4) The Display now reads "READY/PRESS START." At this point, its going
to make a test low speed spin. It will check for vacuum, and allow you to see
if the wafer is centered. Press START.
5) The display will say "TESTING CENTERING," and the chuck will run
at 100RPM for 2 seconds.
6) The display now reads "0 TO RETEST / START." If the wafer is not
properly centered you can adjust it, close the lid, press 0 and retest.
7) When the wafer is centered, press START. The spinner will now run the full
program automatically. The display will update to show times and speeds during
each spin step.
8) When the program finishes, the display will read "UNLOAD SPIN CHUCK,"
and it will beep until the wafer is removed.
NOTE: to abort a spin program in process, press STOP.