Utah-94-721002-System-Manual.pdf - 第57页
System Manual lñÑçêÇ=få ëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== mä~ëã~ä~ Ä póëíÉã=NMM WA F E R SUPPO RT PULLEY WHEEL 1 (DRIVEN) PULLEY WHEEL 2 PULLEY WH EEL 3 (A TT AC HED TO CARRIAGE) PULLEY WH EEL 4 (A TT ACHED TO WA F E R S U P…
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The load lock, shown in Fig 3.10, is fabricated from aluminium and incorporates a hinged lid
containing a view port. The chamber is pumped by a rotary pump or a turbomolecular pump
with the pressure being detected by an appropriate vacuum gauge mounted on the chamber
base plate. A pneumatically operated gate valve enables the load lock chamber to be isolated
from the processing chamber.
The wafer is transported from the load lock into the processing chamber on a wafer support,
which runs on a carriage, which in turn runs on a track.
VACUUM
GAUGE
PUMPING
PORT
FEEDTHROUGH
FOR WIRING
TO PHOTO DIODES
DC MOTOR
AND
REDUCTION
GEAR BOX
TRACK
WAFER
SUPPORT
PNEUMATIC
GATE VALVE
CHAMBER
SEAL
Fig 3.10: Automatic load lock, side view
The wafer transport mechanism, shown in Fig 3.9, comprises the following main components:
a) A Direct Current (DC) motor and associated reduction gearbox located outside the
load lock with the drive shaft entering the load lock through a vacuum seal.
b) Two steel belts each carried by two pulley wheels.
c) A track fixed to the load lock baseplate.
d) A carriage, which runs linearly along the track. The carriage is attached to Steel
Belt 1.
e) A wafer support mounted on the carriage. The wafer support runs linearly along the
carriage and is attached to Steel Belt 2.
Description
UC Davis 94-721001 Issue 1: March 06 Page 3-20 of 22 Printed: 22-Mar-06, 7:29
System Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== mä~ëã~ä~Ä póëíÉã=NMM
WAFER
SUPPORT
PULLEY
WHEEL 1
(DRIVEN)
PULLEY
WHEEL 2
PULLEY
WHEEL 3
(ATTACHED TO
CARRIAGE)
PULLEY
WHEEL 4
(ATTACHED TO
WAFER SUPPORT)
STEEL
BELT 1
STEEL
BELT 2
CARRIAGE
(ATTACHED TO
STEEL BELT 1)
PHOTO
DIODE 1
PHOTO
DIODE 2
TRACK
BELT RETAINING
POST
Fig 3.11: Automatic load lock wafer transport mechanism
Before operation, the Wafer Support is fully retracted into the load lock. To load a wafer into
the process chamber the following sequence of events occurs:
1) The operator opens the load lock door, places the wafer onto the Wafer Support,
and then closes the load lock door.
2) The load lock chamber is pumped down to base pressure.
3) The pneumatically operated gate valve is opened.
4) The DC Motor drives Steel Belt 1 via Pulley Wheel 1. Note that Pulley Wheels 1 and 2
are mounted on the load lock baseplate. As Steel Belt 1 is driven, it moves the
Carriage, which is attached to it.
5) As the carriage travels, it causes Steel Belt 2 to travel around Pulley Wheels 3 and 4.
Note that Pulley Wheels 3 and 4 are attached to the carriage and Steel Belt 2 is
prevented from moving with respect to the load lock chassis by the retaining post.
Description
Printed: 22-Mar-06, 7:29 Page 3-21 of 22 UC Davis 94-721001 Issue 1: March 06
mä~ëã~ä~Ä póëíÉã=NMM lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual
As Steel Belt 2 travels with respect to the Carriage, it causes the Wafer Support
attached to it to travel along the Carriage.
6) As the Wafer Support reaches the end of its travel, a hole in Steel Belt 1 is detected
by Photo Diode 2 to stop the DC Motor.
7) The wafer is lifted from the wafer support by a wafer lift within the processing
chamber, the wafer support is withdrawn from the chamber, and the wafer is
lowered onto the processing table by the wafer lift.
8) As the Wafer Support reaches its fully retracted position within the load lock, the
hole in Steel Belt 1 is detected by Photo Diode 1 to stop the DC motor.
9) The gate valve is closed and the load lock can be vented if required.
The above sequence of events is repeated to remove the wafer from the processing chamber.
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The automatic load lock end effector (wafer support) can accommodate wafer diameters of
3” to 8”. See Section 6 (Maintenance) for the end effector wafer size adjustment procedure.
Description
UC Davis 94-721001 Issue 1: March 06 Page 3-22 of 22 Printed: 22-Mar-06, 7:29