Chapter 2.7
Sink7
(VLSI)
(sink7)
1.0
Title
Sink7 in the VLSI area
2.0
Purpose
This document has specific information about wet sink7,
Microlab’s MOS and Non-MOS 6” sink.
3.0
Scope
Wet Sink7 provides a Big Batch silicon etch bath, a
hot phosphoric acid bath, and two HF tanks as well as two DI water rinse
followed by a quick dump. Each chemical bath and/or tank is clearly labeled.
4.0
Applicable Documents
Revision
History
4.1
Heated
Phosphoric Acid Etching of Silicon Nitride - Concentration and Temperature
Control
4.2
Chapter 2.3 of
the lab manual (Wet Sinks and Spin Dryers)
4.3 Chapter 2.1 of the lab manual, which explains wafer boxes, tweezers, and other tool cleaning prior to using VLSI sink.
5.0
Definitions & Process Terminology
5.1
Full Plenum Lockout
Alarm: Early warning alarm
indicating sink drain failure.
5.2
Quick dump rinse
(QDR): DI water fills the sink
followed by a quick dump to get ride of excess acid and/or contaminants.
5.3
Spin Rinse Dryer
(SRD): DI rinse followed by dry
cycle.
6.0
Safety
Never touch any
surface while wearing chemical-resistant gloves that other lab members may come
into contact with, such as the table tops, door handles, computer keyboards,
face shields, aprons, etc. If you need to step away from the sink at any time,
rinse off gloves at the glove wash, dry with techni-cloths, and put away in
your drawer until you are ready to resume your work at the sink.
Follow general safety guidelines for the
lab safety rules outlined in Chapter 2.3
and the following:
6.1
This sink contains a Big Batch silicon etch bath, a hot
phosphoric acid bath, and two HF tanks; therefore appropriate safety attire
should be worn while working at this station. This means that chemically
resistant gloves on top of the surgical gloves, face shield, and apron have to
be worn while working at or around sink7. Do not use metal tweezers at this
sink.
6.2
Do not adjust the heater controllers as they have been
preset to produce proper bath temperatures.
6.3
Only use chemically resistance
cassettes provided at the station (Teflon type). Failure to do so can cause
damage to the station and/or compromise the operator’s safety.
6.4
Dwyer
Photohelic Exhaust Flow Meter (Figure
5): Monitors the sink exhaust flow and will shut down all electricity and
water to the sink if there is too much or too little flow. An alarm will sound;
press the red SILENCE button (Figure 4) and promptly
report on FAULTS.
6.5
MPC-901 Emergency Alarm (Figure
4): Cuts power to the sink in emergencies. Push the big red STOP button (Figure 4) to cut the power to this sink. Report promptly on
FAULTS.
6.6
Glove Wash: Located in the front center of this sink; water
spray is sensor activated.
7.0
Statistical/Process Data
N/A
8.0
Available Processes, Gases, Process
Big Batch silicon etch bath, hot phosphoric acid bath, and two drainable HF tanks are available at this sink as well as two quick dump rinsers to properly clean the wafers prior to going into the 6” spin rinse dryer (top SRD on the rack.)
|
Bath |
Chemical |
Temperature |
|
Left-Heated Bath |
Big Batch Silicon Etch |
60ºC |
|
Right-Heated Bath |
Hot Phosphoric Acid |
160ºC |
|
Left Non-Heated Tank |
Non-MOS clean HF |
N/A |
|
Right Non-Heated Tank |
MOS-clean HF |
N/A |
9.0
Equipment Operation
The sink operation is relatively easy. The main difference between the old and new style VLSI sinks is that at the new sinks members invoke the dump rinse cycle from a keypad mounted on the face of the station (one for each quick dump rinse tank).
9.1
Control
Key Description
There are six control/displays at this station, see
Figures & Schematics. The two MPC-100 (Figure 3)
control panels are for the heated baths: the one on the left is for the Big
Batch silicon etch, the one on the right for the hot phosphoric bath. The two MICROKLEEN RINSE (Figure 1) control panels are for the two quick
dump rinse (QDR) stations. Each QDR is currently set up for two dump rinse
cycles. Wafers are initially showered with DI water followed by two DI
fill-dump cycles. These cycles end with wafers submerged in the water for
operator to extract and place them in SRD. See Figures & Schematics for
more details. The station performs an automatic self-cleaning, every 60 minutes
by one QDR cycle. The MICROTIMER (Figure 2) control panel timers for the HF baths
are preset to 15 minutes.
POWER Turns
on the control panel.
START Begins a process cycle at any of
the control/display panels.
STOP/RESET Stops or
interrupts a process cycle at any time.
SAVE/SIL Silences
the acid bath alarm.
HOLD Stops heating the Big Batch silicon
etch or hot phosphoric acid bath corresponding to the control/ display panels.
Press HOLD again or RETURN to reactivate the heater.
DRAIN Press twice to empty the
baths/tanks. Make sure chemicals baths are sufficiently cooled down before
draining. To only drain a small amount, press the DRAIN button twice,
then once again when you want to stop the draining.
9.2 Quick
Dump Rinse Operation
9.2.1
Place wafers in the
tank; tank initially should be full of DI water.
9.2.2
Press START
button to activate the dump rinse cycle (Figure 1). It
will cycle down from 2 to 1 then show 0 in the display window. At the end of
the two cycles a beeping alarm will sound. Press STOP/RESET to silence
the alarm. Upon completion of two rinse cycles remove wafers and place in SRD.
9.2.3
Note: Dump the QDR water by pressing the OPEN
button. This will open the gate at the bottom of the sink to drain the water.
Press STOP/RESET to close the gate after the water is drained. Leave the
QDR with no water in it and with closed lid, before leaving the station.
9.3 Room
Temperature HF Controllers (Microtimer Operation)
9.3.1 Place your wafers in the
desired HF acid bath (left bath is designated non-MOS clean, right bath is
designated MOS-clean).
9.3.2 Press the START
button if you wish to use the 15-minute preset timer; use of this is optional (Figure 2).
9.3.3
Press STOP/RESET
button to end or interrupt the cycle.
9.3.4
To reset the timer at
end of cycle, press STOP/RESET once again.
9.3.5
Remove wafers and rinse
in either of the quick dump rinsers.
9.4 Hot
Bath Controller for Big Batch Silicon or Hot Phosphoric Bath (MPC-100)
9.4.1 Place your wafers in desired bath, either
the Big Batch silicon etch (staff use only) or the hot phosphoric bath.
9.4.2 Press time/start button to start the etch
process cycle with the preset time and temperature (Figure 3).
9.4.3 When your etch is completed after the
preset time, hit the TIME STOP/RESET button to reset the timer.
9.4.4
Remove your wafers and
rinse in quick dump rinse #1 for the Big Batch silicon etch or quick dump rinse
#2 for the hot phosphoric.
9.5
Changing Acid(s)
in Sink7
9.5.1
Big Batch Silicon
Etch (Figure 3):
9.5.1.1
Press the HOLD
button once on the MPC-100 temperature controller panel so that the bath
temperature will cool down to 60ºC. Note: LED light next to Heat,
under status column, goes off.
9.5.1.2
Next, press the DRAIN
button twice to empty the bath. Rinse bath with DI water after completely
drained. The timer is set for 10 minutes. Do not put solution in bath before
this time has elapsed.
9.5.1.3
Press DRAIN
button again to close the gate on the bottom of the tank. Fill the bath with
new Big Batch silicon etch.
9.5.1.4
Press HOLD button
to restart the heater. LED adjacent to Heat, under status column, turns
on.
9.5.2
Room Temperature HF
Baths (Figure 2):
9.5.2.1
Press the AMBIENT
TANK #1/#2 DRAIN green button.
9.5.2.2
Rinse the bath with DI
water once the tank is empty.
9.5.2.3
Press the AMBIENT
TANK #1/#2 DRAIN green button again.
9.5.2.4
Fill the non-MOS clean
or MOS clean HF in the appropriate acid tank accordingly.
9.5.3
Hot Phosphoric Acid
Bath (Figure 3):
9.5.3.1
Press the HOLD
button on the MPC-100 temperature controller panel so that the bath temperature
will cool down to 74.5ºC.
9.5.3.2
Next press the DRAIN
button twice to empty the bath. Rinse bath with DI water after completely
drained. The drain timer is set for 10 minutes.
9.5.3.3
Press DRAIN
button again to close the gate on the bottom of the tank. Fill the bath with
new phosphoric acid.
9.5.3.4
Press HOLD
button to restart the heater.
9.6
Control Panel
Programs are shown in the appendix.
9.6.1
The parameter codes for
the programs on the MPC-100 temperature controllers and Microkleen Rinse are listed
on Table 1 and Table 2 in the
appendix. The parameter codes are not to be altered by the Microlab members.
Please use them as your reference check only.
10.0
Troubleshooting Guidelines
10.1
Rinse cycle stopped in
the middle QDR cycles: press open to dump the water out. Press stop/reset key
followed by restart the dump rinse cycle from the start.
10.2
No Power To Sink:
Several issues can shut the system down.
10.2.1
Power To System Off (Figure 4): Press power ON if
no issues have been reported on the Wand or if the system is not under
technician’s control.
10.2.2
Photohelic
Differential Pressure Reading (Figure 5) is outside limits (two red bars): Consult with
staff to check house exhaust pressure.
10.2.3
Plenum Full: The plenum on this system is directly connected to
fabwide (sink6). Full plenum in sink6 will also stop sink7 operation.
Spin Rinse/Dryer HElp
Messages
|
HELP-0 Power
Failure
|
The
power failed while the unit was operating. Check the electrical lines in the
unit, and for a blown fuse. Press START to reset the microprocessor.
The rinser/dryer indexes the rotor and resets to the beginning of the
interrupted cycle. |
|
HELP-1 Bladder Pressure |
There
is inadequate nitrogen pressure to inflate the door seal. Check the door
bladder, the nitrogren pressure, and the pressure switch. Be sure there is
20-21 psi on RG2 and that the pressure switch turns off when the pressure
reaches 17-18 psi. |
|
HELP-2 Nitrogen Pres |
There
is insufficient pressure in the system nitrogen line. Check the nitrogen
pressure switch (PSW1). It should be set to approximately 13 psi. Check the
system line for leaks. Be sure that the pressure at RG1 is 23 psi dynamic.
Check the Clean Coil thermostat and reset if necessary. |
|
HELP-3 Door Open |
The
door is not completely closed. Check the door. If the door is properly
aligned, check the micro-swtich actuating arm. |
|
HELP-4 Index Failure |
The
unit is not able to index the rotor. Check the rotor positioner. |
|
HELP-5 Excessive Speed |
The
rotor speed has exceeded 3400 RPM. Retry the cycle a few minutes. If the
problem persists, there is a hardware problem. Call maintenance or VERTEQ for
assistance. |
11.0
Figures
and Schematics
AMBIENT TANK #1 DRAIN
Figure 1 –
Quick Dump Rinse (QDR) Figure 2 – Room
Temperature Bath Timer Controller
Figure 3 –
Hot Bath Temperature Controller
Figure 4 –
Main System Power/Alarm Controller
Figure 5 –
Photohelic Differential Pressure Gauge
12.0 Appendix