Chapter 3.5
APT Chrome Process
(aptchrome)
1.0
Title
APT Chrome Process
2.0
Purpose
The APT Chrome Mask Developer
is an automated photomask processing unit for chrome and iron oxide masks
which have been exposed in the pattern generator.
3.0
Scope
This chapter describes the chrome process used in the APT chrome
unit on the left in R1. All programs to which we refer in this manual are
listed in Section 9.3. Please note that sink12 must be enabled when using the
APT as the chemicals from the APTs drain directly into the plenum of sink12.
The aptchrome mask developer accommodates masks in the following sizes: 2.5”,
4”, 5”, 6” and 7”.
4.0
Applicable Documents
5.0
Definitions and Process Terminology
N/A
6.0
Safety
Before you proceed, please note the
following: The door to the process chamber should be kept closed and latched
at all times except when loading or unloading masks.
7.0
Statistical/Process Data
N/A
8.0
Available Process, Gases, Process Notes
N/A
9.0
Equipment Operation
9.1 Enable the aptchrome on the Wand.
9.2 The system power to the aptchrome can be turned
on by flicking on the blue “power on” rocker switch which is located on the
left side of the aptchrome. The program status will then be displayed on the
program recipe display screen on the front panel. Processing programs 90
(develop), 91 (etch), 92 (strip resist), 93 (rinse and dry),and 99 (test lines)
are each separately activated by a red rocker switch that will illuminate when
selected. The STOP/RESET is a square red button and the recipe START a square
black button. In addition there is
white rocker switch for manual
override; this is located next to the red Prog.99 switch. This feature is most useful when you want to
slightly overetch a plate. To utilize this feature, start the etch recipe then
engage the override switch before the etchant stops dispensing. The display
screen will show “MANUAL” then how many
seconds the etchant is dispensing. When the desired overetch time has been
realized, turn the override switch off
and the recipe will continue on to the next steps until the program is
completed. Follow the same steps for overdevelop.
9.3 To
operate the tool, the program recipe display screen will prompt you to “SELECT
A PROGRAM AND PRESS START.” Select
a recipe by pressing the desired recipe rocker switch which will illuminate
when selected. Next press the START button. Once a recipe has been started, it
will continue until it finishes and the program recipe display screen will read
“END OF PROGRAM.” While the recipe is running, the display on the screen will
show how much time has elapsed since the start of the recipe.
if the red “STOP/RESET” button is
pressed, the tool will immediately cancel the remainder of the recipe and stop
whatever it is doing. The program recipe display screen show you that the recipe has
been stopped and will ask you to reset the system by pressing the “STOP/RESET”
button once more. The display will once again prompt you to select a recipe and
press “START.”
Only one recipe may be run at a time:
If
more than one is selected and the START button is pressed, neither recipe will
run.
Important note: The “STOP/RESET” button does exactly that:
it stops the recipe at once and does not automatically skip to the next
step!
9.4
Checking Chemical Lines
Before starting your process, you will run a test program (Program
99- test lines) to check that each chemical is flowing properly at each step.
The chemical(s) should dispense from the nozzle(s) as a fan-shaped spray. The
program is set up to allow each required chemical to spray in sequence, with
water rinses in between. Program 99 is described in Section 9.3.
9.4.1
Select program number 99 – test lines.The lamp is on at all times
during Program 99.
9.4.2
Press START button.
9.4.3
When the program starts, make sure that the desired chemical
starts to spray out of its respective nozzle (30 seconds.).
9.4.4
Let the water rinse cycle run through (30 seconds). The next
chemical should then begin to spray. Continue in this fashion until you have
worked your way through the program.
9.4.5
If too much water beads up on the door and prevents you from being
able to see through, briefly open the
door and wipe it dry with a techni-cloth. Techni-cloths are kept in a dispenser
on top of the aptchrome.
9.4.6
If everything checks out, proceed to Section 9.3. If there is a problem, contact the process
staff for help and report the problem on the Wand using the FAULTS program.
9.5
Processing Masks
9.5.1
Run the develop Program 90
without a plate initially to make sure the lines are clear.
9.5.2
Load mask, chrome side up, onto the spinner, seating all 4 corners
securely so that it does not fly off and break during the spin.
9.5.3
Close and latch the door and select the desired program number.
9.5.4
Press START.
9.5.4.1
Develop: Program 90
Program 90, which is the initial develop step, does not turn on
the lamp during the entire process so that the plates are not exposed. After a
standard develop step the plate should be inspected for complete development at
the Leitz microscope in R2.
9.5.4.2
Etch: Program 91
Beginning with the etch step, the lamp will be turned on for all steps.
The aptchrome endpoint detectors automatically determine the completion of the
metal etching process. After this step it is recommended to inspect the plate
at the Leitz microscope in R2.
9.5.4.3
Photoresist Strip: Program 92
The remaining photoresist is exposed with the lamp in the first
step and then removed with developer concentrate. Program 92 is a "strip
only" process, which removes the photoresist from the mask following the
develop and etch steps.
9.5.5
When the process is finished, check to see if the plate is
completely dry on both sides. If not, use the N2 anti-static gun in R2 mounted
at the pattern generator chamber to blow it dry.
9.5.6
Run Program 93 to water rinse the aptchrome chamber.
9.5.7
When Program 93 is finished, unlatch the door and use the DI water
deck gun at sink12 to rinse the interior of the chamber.
9.5.8
Use a techni-cloth wetted with Nova Clean spray to wipe and clean
the interior of the latched window; techni-cloths can be found in a dispenser
which is on top of the aptchrome; the Nova Clean spray is there as well.
9.5.9
Disable the aptchrome on the Wand.
9.5.10
Clean up the sink and any chemical spills on the APT surfaces as
well.
9.6
Programs
The programs stored in the APT Chrome Developing system are listed
below.
Program 99 –
Chrome Process Test
|
Step |
Chemical |
Output |
Description |
Spin Speed (103 RPM) |
Time (sec.) |
|
1 |
Shipley Microposit Developer 452 |
Lamp on |
Developer Nozzle |
.00 |
30 |
|
2 |
Water Rinse |
Lamp on |
Top/Bottom Rinse |
.00 |
30 |
|
3 |
Concentrated Chromium Etchant CR-7 |
Lamp on |
Etchant Nozzle |
.00 |
30 |
|
4 |
Water Rinse |
Lamp on |
Top/Bottom Rinse |
.00 |
30 |
|
5 |
Shipley Microposit Developer 452 |
Lamp on |
Stripper Nozzle |
.00 |
30 |
|
6 |
Water Rinse |
Lamp on |
Top/Bottom Rinse |
.00 |
30 |
Program 90 – Develop
Only
|
Step |
Chemical |
Output |
Description |
Spin Speed (103 RPM) |
Time (sec.) |
|
1 |
Water Rinse |
Lamp off |
Top/Bottom Rinse |
.22 |
10 |
|
2 |
Shipley Microposit Developer 452 |
Lamp off |
Developer Nozzle |
.22 |
75 |
|
3 |
Water Rinse |
Lamp off |
Top/Bottom Rinse |
.22 |
45 |
|
4 |
Spin Dry |
Lamp off |
(Spindry) |
.95 |
120 |
Program 91 – Etch
Only
|
Step |
Chemical |
Output |
Description |
Spin Speed (103 RPM) |
Time (sec.) |
|
1 |
Water Rinse |
Lamp on |
Top/Bottom Rinse |
.22 |
10 |
|
2 |
Concentrated Chromium Etchant CR-7 |
Lamp on |
Etchant Nozzle |
.22 |
100 |
|
3 |
Water Rinse |
Lamp on |
Top/Bottom Rinse |
.22 |
45 |
|
4 |
Spin Dry |
Lamp on |
(Spindry) |
.95 |
120 |
Program 92 –
Strip Only
|
Step |
Chemical |
Output |
Description |
Spin Speed (103 RPM) |
Time (sec.) |
|
1 |
Spin |
Lamp on |
(Lamp on) |
.22 |
480 |
|
2 |
Water Rinse |
Lamp on |
Top/Bottom Rinse |
.22 |
10 |
|
3 |
Shipley Microposit Developer 452 |
Lamp on |
Stripper Nozzle |
.22 |
60 |
|
4 |
Water Rinse |
Lamp on |
Top/Bottom Rinse |
.22 |
45 |
|
5 |
Spin Dry |
Lamp on |
(Lamp on) |
.95 |
120 |
Program 93- DI
Water Rinse and Spindry
|
Step |
Chemical |
Output |
Description |
Spin Speed (103 RPM) |
Time (sec.) |
|
1 |
DI water |
Lamp on |
Top/Bottom rinse |
.22 |
30 |
|
2 |
Spindry |
Lamp on |
Spindry |
0.95 |
120 |
10.0
Troubleshooting Guidelines
If the program recipe display screen is blank, report on FAULTS
promptly, as this indicates a blown fuse.
11.0
Figures & Schematics
N/A
12.0
Appendix
PLC & Electronics
Program Recovery
Restoration
The new control system was designed to be very reliable, and as a
result, loss of the programs stored in the PLC is highly unlikely. Should any
of the programs ever be lost or become corrupted, the program can easily be
reloaded. Simply connect the cable from the PLC (port located on the front of
the controller) to the laptop computer, open the LOGO program you wish to load,
and press the transfer from PC to LOGO button. See the LOGO user manual for
detailed instructions.
The PLC is basically an array of relays, which are programmed to
open and close in sequence to power the solenoids, motor control circuit, and
lamp relay. See the circuit diagrams in the appendix for details.
There are two motor speed controllers located in the electronics
cabinet on the far right. The back most unit is the “high speed” controller and
is active only for the drying step of each recipe. The front unit is the “low
speed” controller and is active for all other spin steps. The knobs on these
units control the speed, at which the motor is spinning. By holding down the
“ESC” button and simultaneously pressing the “UP” button on the controller, the
PLC will display the current RPM of the motor. Repeating this action will
return you to the normal program display. The ideal setting for the “low speed”
controller is roughly 200 RPM, while the “high speed” controller should be set
anywhere above 1000 RPM.
Pumps and Valves
All of the pumps and chemical control valves are pneumatically
operated via the SMC solenoid manifold. See diagram in appendix for drawing. If
a pump needs to be primed, the orange buttons on the SMC solenoids can be used
to manually power the pumps until the lines are primed.