Tegal Plasmaline 515 procedure rev3

TEGAL PLASAMALINE 515
PHOTORESIST ASHER
Primary contact: Hoc Ngo x68923
PREPARED BY: Eric Chang & Hoc Ngo DATE: 09/29/00
Jr. Devlp. Engr.
Superusers: Sung Cho x58275
Andy Hung x45774
Joanne Deval x51350
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TEGAL PLASMALINE 515 PHOTORESIST ASHER
1.0 SCOPE
This document establishes the procedures for plasma ashing of photoresist films on silicon,
GaAs, and other substrates in the Nanoelectronics Laboratory.
2.0 APPLICABLE DOCUMENTS
Plasmaline 515 logbook
Plasmaline 515 operation and maintenance manual
3.0 MATERIALS AND EQUIPMENT
Tegal Plasmaline 515 System
Metal Tweezers
Isopropyl Alcohol
Gloves, cleanroom
Cleanroom wipes
Cleanroom mask
Aluminum 4" wafer boat
4” wafer holders
4.0 GENERAL
4.1 Tegal Plasmaline Overview
The Tegal plasma asher uses oxygen and plasma to remove photoresist on silicon,
GaAs and other substrates. It can also be used to remove resist residue after
development (descum)
4.2 Vacuum Integrity Maintenance
It is necessary to maintain a low background pressure for proper operation of this
equipment. To avoid contamination these practices are to be followed:
4.2.1 Never touch any part(s) inside the chamber or part(s) going into the
chamber with bare hands or contaminated gloves.
4.2.2 Handle wafer boat and parts going into the chamber with clean gloves
and/or vacuum system tools.
4.2.3 A cleanroom mask must be worn while the chamber is open.
4.3 Emergency Power Shut-Off
4.3.1 For emergency shut-off, press the red AC OFF button located on the
lower control panel. The white AC ON lamp (located on the lower control
panel) should turn off.
4.3.2 Turn off the Main Power Circuit Breaker is located on the backside of the
system, near the bottom. Its action parameters are:
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5.0 PROCESS PREPARATION
Up Position - Power On (the red POWER lamp located on
upper panel should be illuminated)
Down Position - Power Off (the red POWER lamp should be
illuminated)
Mid Position - Trip Condition: contact a Nanolab engineer
5.1 Tegal Standby Checklist
Review the standby checklist - see Appendix I. The checklist must be performed
before pumping the system.
5.2 Sample Loading
NOTE: At this point you must be wearing clean gloves and a facemask.
6.0 PROCEDURE
5.2.1 Open the chamber door by turning the spring-loaded latch and pulling
forward.
5.2.2 Check the chamber O-ring for debris/particles. If needed, gently wipe the
O-ring with clean wipes.
5.2.3 Remove the aluminum boat. Load samples. Use sample holder for small
pieces, if necessary. Replace the boat containing samples to be etched.
5.2.4 Close the chamber door and be sure the latch is fastened. Pull the latch out
and then fasten down. There is no relative moving between chamber
and chamber door.
6.1 Chamber Pumpdown
6.1.1 If the AC ON lamp/button on the lower control panel is off/dark, press it
in. The AC ON lamp should illuminate. The system’s heater takes about
45 minutes to reach a set temperature of 80°C, at which point the red
TEMP light on the upper panel turns on. The temperature cannot be
changed.
Note: The outside surface of the unit, especially the chamber door, may go
up to 50 o C.
6.1.2 Set the desired etch time, in minutes, with the thumb wheels on the right
side of the process control panel (behind the access door). See etch rate
data in logbook. Record the etch time in the logbook.
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6.1.3 Press the START/COMPLETE lamp/button on the lower control panel to
initiate the process cycle. The white START light should illuminate. After
a short delay, the chamber will automatically pump down to the base
pressure (~85 mTorr).
6.2 Etch Initiation
6.2.1 The oxygen gas will automatically turn on after the base pressure is
achieved. The gas can be checked by reading the flow gauge and the
chamber pressure display on the upper panel. .
The operating pressure should be 0.5Torr +/- 0.1Torr. The gas can be
adjusted to obtain this pressure by turning the flow adjust knob on the
right of the upper panel. Make only small adjustments and allow the
pressure to stabilize.
6.2.2 Read and record the operation pressure in the logbook.
6.2.3 The RF power automatically turns on when process pressure (0.5 Torr) is
achieved after about 45 sec. The red RF ON PROCESS (below the AC
ON light) illuminates.
6.2.4 On the upper panel, press down and hold the power display indicator
switch to FWD. Read the forward RF power and adjust, as needed (using
RF POWER knob on the process control panel behind hinge door) to
obtain 200 W. The reflective power is displayed when the switch is
released.
6.2.4 Read and record the forward and the reflected power. If the reflected
power is > 5 W, turn off the unit by pressing the START/COMPLETE
button, and call Nanolab engineer for assistance.
6.3 Etch Completion
6.3.1 When the ash process is complete the RF power and oxygen gas will
automatically shut off. The chamber will vent automatically and the green
COMPLETE light on the lower control panel will illuminate.
6.3.2 Press the START/COMPLETE lamp/button to turn off the light. Wait a
few seconds for the venting to complete. You can hear a hiss and see the
door push out slightly when the chamber is fully vented.
6.3.3 After the chamber is vented, release the spring-loaded latch and open the
chamber door. Again, you should be wearing a facemask.
6.3.4 Unload samples and return all empty boats and wafer holders to the
chamber.
6.3.5 Close and latch the chamber door.
6.3.6 Complete your logbook entry and clean up the equipment area. Do not
turn the machine off.
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APPENDIX I - TEGAL STANDBY CHECKLIST
Logbook - Last Entry
COMMENTS “OK”
Upper Panel
POWER lamp On/lit (red)
TEMP lamp On/lit (red)
PRESSURE display (LCD) Reads 1
Process Control Panel (behind access door – pull out to open)
TUNING switch AUTO
MODE selector AUTO
HEATER switch ON
PROCESS selector TIMER
TEMP ALERT switch MUTE
Lower Control Panel
AC ON lamp On/lit (white)
RF ON lamp Off/dark
START lamp Off/dark
COMPLETE lamp Off/dark
Backside
Main Power Circuit Breaker Up
N 2 gauge ~5 PSI
O 2 gauge ~5 PSI
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