TRION MINILOCK II RIE ETCH SYSTEM

OPERATING PROCEDURES

Version: 2.0 May 2013

UNIVERSITY OF TEXAS AT ARLINGTON

Nanotechnology Research and Education

Center

This SOP is for reference only. Training from an authorized staff member is required before using this equipment.

1. Description The Trion Minilock II RIE (reactive ion etch) provides anisotropic plasma etching of Gallium Arsenide (GaAs), Aluminum Gallium Arsenide (AlGaAs) and Indium Phosphide (InP) on 1”- 4” diameter wafers and small sample pieces. In addition to this ITO deposited samples may be etched with prior Nanofab management approval.

2. Safety a) This machine uses extremely hazardous gases (BCl3, SiCl4, Cl2, HBr) which may be colorless and

are very corrosive and toxic. Boron Trichloride (BCl3), Silicon Tetrachloride (SiCl4), Hydrogen Bromide (HBr) are colorless gases with a pungent and irritating odor. These gases pose an inhalation and bodily contact hazards which can cause burns to the respiratory track, eyes, skin and mucous membranes. Chlorine (Cl2) is a greenish-yellow colored gas with a distinct, irritating bleach-like odor. This gas also poses an extreme inhalation and bodily contact hazards which can cause burns to the respiratory track, eyes, skin and mucous membranes. Therefore a bleach odor provides a good warning of a release of this gas. Lastly this tool uses Tetrafluoromethane (CF4), Oxygen (O2), Argon (Ar) and Helium( He ) gases which in high concentrations can be asphyxiates. The process gases are normally pumped out of system; however if the process pressure is not being maintained or the system cannot reach base pressure notify NanoFab staff immediately.

b) Before using this tool read the Minilock II RIE material safety data sheets( MSDS) provided. These MSDS’s are located in a binder labeled Minilock II RIE MSDS placed near the tool.

c) Read any posted NanoFab Engineering Change Notices (ECN) for any hardware, process or safety changes before running the tool.

d) This tool continuously monitors, displays and records the toxic gas PPM (parts per million) levels using the Drager Polytron 2 XP Transmitters and DraegerGard controller. If a PPM level exceeds an alarm set point the controller will relay an audible and visual alarm throughout the building. If the Minilock II RIE system’s alarm light tower YELLOW light goes ON immediately leave the NanoFab building informing others to leave on your way out. If the light tower’s RED alarm light and audible alarm goes ON immediately leave the NanoFab building through the closest and safest emergency exit and wait for emergency personnel to arrive. DO NOT operate this machine if the Drager Polytron 2 XP Transmitters display any warnings, faults or if any RED leds are ON. If any warning, alarms or RED leds are ON notify NanoFab staff immediately.

e) DO NOT operate this machine or ABORT your process if the acid exhaust Magnehelic gauge located above the tool is < 0.50 ’’of water. Do not let your process continue below < 0.50 ’’of acid exhaust!

f) This machine uses RF frequency power. DO NOT operate this machine with any RF component enclosures/panels open

g) This machine has an EMO (Emergency Off) switch/button mounted on the left side panel. The EMO switch should be pressed only in an emergency. An emergency would be fire, smoke, gas release, electrocution hazards, and an injury to anyone using this particular piece of equipment. If the EMO is pressed notify NanoFab staff immediately.

h) Keep your fingers clear of the Load lock lid when loading/unloading wafers. Do not place anything on the Load lock lid.

The following visual aide pictures are for Safety sections 2a) to 2h)

2a ) 2a-f )

2c ) 2c )

2d ) 2d ) > 0.50 “ of water

3. Requirements/Restrictions

a) Read the NanoFab Response Plan at the end of this SOP.

b) Read the Minilock II RIE material safety data sheets (MSDS) provided.

c) You must be a qualified user on Minilock II RIE.

d) The RIE etcher is used to anisotropically etch 1”- 4” diameter Gallium Arsenide(GaAs), Aluminum Gallium Arsenide (AlGaAs) and Indium Phosphide (InP) layers and wafers ONLY. Sample pieces (GaAs, AlGaAs, InP) and 1”- 3” diameter wafers can be etched ONLY if they are positioned on top of a 4” diameter Nitride, Oxide, or resist coated wafer. ITO coated silicon wafers may also be etched with prior Nanofab management approval.

e) All wafers (etch and carrier) must not have any edge chips, nicks, or cracks. The backside must be clean and flat (no warps, dimples, defects).

f) All carrier wafers must have an adequate thickness of Nitride, Oxide or Resist to minimize possible dopant and contamination from an uncoated carrier wafer.

g) Masking Materials NOT Allowed: NO METAL MASK is allowed.

h) Masking Materials Allowed: Oxide hard masks (Sputter, Thermal or PECVD), Nitride hard mask (Sputter or PECVD), positive resist mask (Shipley 1.3, 1.8, AZ 9620; PR1, ZEP 520 resist) and negative resist mask. NanoFab staff approval for other masking materials is required.

i) A 4” diameter Oxide or Nitride deposited wafer needs to be loaded for all chamber plasma cleans.

j) Minilock II RIE can ONLY be used Monday-Friday’s from 8am to 6pm.

(Excluding Holidays).

k) Read any posted NanoFab Engineering Change Notices (ECN) for any hardware, process or safety changes before running the tool

.

l) DO NOT leave the Minilock II RIE for more than 30 minutes at a time during a run. The user must check the status every 30 minutes to verify there are no alarms.

m) DO NOT operate this machine or ABORT your process if the acid exhaust Magnehelic gauge located above the tool is < 0.50 “ of water. DO NOT let your process continue below 0.50” of acid exhaust!

n) Users can only run NanoFab recipes named :

TrionInP_ TrionGaAs_deg Zhou0_ CLEAN

o) The ONLY plasma etch recipe changes allowed without staff approval is the step/ etch TIME

parameter.

p) Plasma etch recipes other than NanoFab recipes can be run with staff approval ONLY. Save these other recipes to dedicated NanoFab-Minilock USB memory stick (E :\) and not to the system hard drive. NanoFab memory stick must not be removed or taken outside NanoFab.

q) Users are not allowed to VENT or OPEN the Main Chamber Lid. If there is process or hardware problem that requires chamber venting notify NanoFab staff to perform a chamber vent sequence

4. Minilock II RIE System Checks

(Minilock II RIE System checks are in the clean room and chase 3 sides of the system)

a) Check to ensure all the Drager Polytron 2 XP Transmitters ( clean room and chase ) have NO warnings or faults displayed and check if any RED leds are ON. If any warning or alarms are displayed or the RED leds are ON notify NanoFab immediately.

b) Check to ensure the acid exhaust Magnehelic gauge located above the tool is > 0.50 “ of water. DO NOT operate this machine or ABORT your wafer processing if the acid exhaust Magnehelic gauge is < 0.50 “ of water and contact NanoFab staff immediately.

c) Check to ensure the top electrode (ICP) and bottom electrode (RIE) RF generators water flow meters are displaying > 1 LPM and there are no water leaks.

d) Go to the service chase and turn ON the Neslab chiller for the bottom electrode by pressing the I/O button on the front panel of the chiller. Ensure the chiller setpoint temperature is correct for your process and verify there are no fluid leaks. Failure to turn on the lower electrode chiller will result in RIE generator power faults when the system is operated.

e) Check to ensure the Turbo Pump Controller is on and rotating @ 19,800 rpm.

f) Check to ensure the Matching Network toggle switch (on the system front panel) is set to AUTO.

The following visual aide pictures are for Minilock II RIE System Checks

(Clean Room side of system) sections 4a) to 4e) .

4a ) 4a ) 4b ) > 0.50 “ of water

4c ) 4d ) 20+/-1c

4e ) 4f )

5. Operating Procedure a) When you first approach the system you may see one of these computer touch screen or MS Windows screen displays :

i)Stand by ii) MS Desktop iii) Main Menu

For screen i) check the Main Chamber (process) base pressure is 0-2 mtorr and the Load Lock Chamber base pressure ≤ 20 mtorr. If either of these pressures is higher than specified contact NanoFab staff .

If the Main Chamber pressure is ≤ 2 mtorr and Load Lock ≤ 20 mtorr press Cancel to access the Main Menu.

Main Menu

b) For screen ii) press shortcut to PLC_1.36 icon and wait for system hardware to initialize to get to screen iii) Main Menu then press Stand By Mode and wait for system to go into Stand By mode to check if both chamber pressures are in spec (Main Chamber pressure is ≤ 2 mtorr and

Load Lock ≤ 20 mtorr). For screen iii) Main Menu press Stand By Mode and wait for system to go into Stand By mode (about 10 min) to check if both chamber pressures are in spec (Main Chamber pressure is ≤ 2

mtorr and Load Lock ≤ 20 mtorr ).

c) If the Main Chamber (process) base pressure is 0-2 mtorr and the Load Lock Chamber base pressure ≤ 20mtorr press Cancel to access Main Menu. If either of these pressures is higher than specified contact NanoFab staff .

Main Menu

d) In the MAIN Menu Recipe Control tab press Load/Edit Recipe button to access the Recipe Parameter page

Main Menu

e) In the Recipe Parameter page press Recipe From Disk button to access Chamber # 1 recipe page.

Recipe Parameter page Chamber # 1 recipe page

Users can only run recipes named :

TrionInP_ TrionGaAs_deg Zhou0_ CLEAN

g) In the Chamber # 1 recipe page press Hard Drive, Next Screen (or Previous Screen) or

External Drive button to have access to the recipe you want to run.

Chamber # 1 recipe page

g) Wait for the recipe to down load.

h) After the recipe is downloaded it will appear in the Current Recipe header. Then press EXIT to access the Recipe Parameter page.

Recipe Parameter page

i) In the Recipe Parameter page to verify or change the etch recipe set points for any step in your

process sequence press the Step # box and process step window will pop up. Enter the Step # you need to access then press Enter.

j) In the Recipe Parameter page for a selected Step # to change the step time (step time for Chamber pump-out, MFC gas flow, ICP or RIE on time ) press the Process Time box and the Process Time window will pop up. Enter the new step time (in seconds) then press Enter.

(The ONLY plasma etch recipe changes allowed without staff approval is the step/etch TIME parameter!)

k) Other recipe parameter (pressure, gas flow, ICP and RIE power levels) may be changes with

NanoFab approval. Save these other recipes to dedicated NanoFab-Minilock USB memory stick (E :\) and not to the system hard drive.

pressure,power,gas flow Save changes to (E:\) DO NOT Save changes to HD (C:\)

J) NanoFab, TRION, User Made staff approved recipes MUST have a He purge step at the end of the recipe sequence. This is to purge the Main Chamber and prevent hazardous gases from back flowing into the Load Lock chamber.

Use the following purge step (150 mtorr , 80 sccm Ar , 240 secs )

l) After the process sequence step times have been changed press EXIT.

m) To down load the recipe changes to the Main Screen press Download Recipe button or press Not Now button to exit the Recipe Parameter page without saving recipe changes.

n) After pressing Download Recipe to load the recipe or NOT NOW to exit without saving you will return to the Main Menu to access other recipes, go to Stand By Mode or start Automatic Process Control.

Recipe Downloding Main Menu

o) To start wafer loading and your etch sequence press Full Auto Process Start in the Automatic Process Control window. In Automatic Process Control mode wafer loading, etching (up to 15 steps) and unloading sequences are done automatically. Before running your device wafer make sure you have loaded the correct recipe and wafer.

p) After pressing Full Auto Process Start message will pop up “Do you wish to VENT the load lock first ? “

Press Do NOT Vent if your wafer is already in the load lock ( i.e. re-etching your wafer). Press Vent Lock First if your wafer is NOT in the load lock.

q) Pressing Vent Lock First button the Load Lock will begin the vent sequence and after venting the Load lock lid will open . Be sure not to place anything on the Load lock lid.

r) Place your 4” wafer or bonded samples on a 4” carrier wafer on the robot arm. The wafer should be placed such that the rounded wafer edge mates with the curved robot spacer

plate. After the wafer is loaded press OK and keep your fingers clear as the Load lock lid closes, or press Cancel to abort the loading sequence.

Depending on how long the Load Lock has been vented the loading sequence may take up to 4 minutes.

Note: In Automatic Process Control mode wafer loading, etching (up to 15 steps) and unloading sequences are done automatically. Before running your device wafers make sure you have loaded the correct recipe and wafer.

s) Wait for Load Wafer sequence to finish. Do not press the Abort unless an emergency arises.

t) After the load sequence is completed the Chamber Status is displayed and the etch sequence

begins.

u) During the etch sequence the only button active in the Chamber Status screen is the Abort button.

If the Abort button is pressed all gases and power will shut off and automatically unload the wafer.

If the Abort button is pressed all RF power and gas flows are turned OFF. The Unload Wafer sequence will begin automatically. After the wafer has transferred to the Load Lock Chamber the following The “Unload Complete” message will be displayed: Press OK .

Press OK

v) After pressing OK the message “Do you want to VENT the LOAD LOCK after unloading the wafer ?“ will be displayed. Press Cancel to leave the wafer in the Load Lock vacuum (Do NOT press OK).

w) FOR SAFETY REASONS LEAVE THE WAFER IN THE LOAD LOCK UNDER VACUUM AND

CALL NANOFAB STAFF TO PURGE CHAMBER AND REMOVE THE WAFER, OTHERWISE RESIDUAL TOXIC GASES MAY BE RELEASE FROM THE LOAD LOCK CHAMBER !!.

x) After the etch recipe sequence is completed (programmed etch time count down) the wafer will

unload automatically (in Automatic Process Control mode there is no Process Complete message).

Wait for Unload Wafer sequence to finish. Do not press the Abort unless an emergency arises.

y) Remove your wafer from the Load Lock then touch the OK button. Keep your fingers clear as the Load Lock lid closes and the system returns to Main Menu.

Remove Wafer Press OK Main Menu

z) When you are finished etching your wafers start the gas manifold cycle purge routine and leave the

system in stand by mode by touching the Stand By Mode button. After the gas manifold cycle purge is completed the system will go into Stand By Mode

aa) Enter the required information in the logbook.

One logbook entry per wafer processed. IF your wafer is the 5th wafer etched from the previous plasma clean download the CLEAN recipe as per section: 5. Operating Procedure d) through r) then load the dedicated plasma clean wafer

(located by the machine) and run the CLEAN recipe..

Main Menu

bb) After unloading the plasma clean wafer start the gas manifold cycle purge routine and leave the

system in stand by mode by touching the Stand By Mode button. After the gas manifold cycle purge is completed the system will go into Stand By Mode.

cc) Return to the service chase behind the system and turn OFF the Neslab chiller for the lower

electrode. To turn OFF the chiller, on the chillers front panel press the I/O button and then press the UP/YES arrow. A 30 second count down will appear on the display and then the chiller will power itself off.

dd) The system is now secure.

6. Abort Procedure/ Faults/ Problem Troubleshooting a) Reasons to abort a run: wrong recipe, wrong recipe set points, wrong wafer, set point reads not being met, gas distribution plate (Showerhead) arcing, unstable plasma,

excessive chamber particles , Magnehelic guage located above the tool is < 0.50 “ of water. DO NOT let your process continue below 0.50” of acid exhaust, after 10 to 15 seconds the top or bottom electrode’s Reflected Power is > 5% of Forward Power.

> 0.50 “ of water- OK

b) If you need to abort the process touch the Abort button . All gases and power will turn OFF once this button is pressed..

Follow the Abort procedure as per section: 5. Operating Procedure u) through w) .

FOR SAFETY REASONS ABORT PER SECTION: 5. Operating Procedure u) through w) . LEAVE THE WAFER IN THE LOAD LOCK UNDER VACUUM AND CALL NANOFAB STAFF TO PURGE CHAMBER AND REMOVE THE WAFER, OTHERWISE RESIDUAL TOXIC GASES MAY BE RELEASE FROM THE LOAD LOCK CHAMBER !!.

c) If the Abort is due to equipment malfunction notify NanoFab staff and note it in the logbook.

d) If you abort the process due to wafer transfer problems notify NanoFab staff and note it in the

logbook.

e) If the wafer is NOT on the chuck or you cannot determine where the wafer is leave the wafer in the chamber, notify NanoFab staff and note it in the logbook that a wafer is stuck in the chamber.

f) For any fault messages (pressure, gas flow, temperature, water flow) recheck section

4. Minilock II RIE System Checks for possible cause, notify NanoFab staff and note it in the

logbook.

g) For various machine problems such as wafer stuck in the chamber, broken wafer, scratches on wafer notify NanoFab staff and note it in the logbook.

h) For various wafer problems such as under etched wafers, over etched wafers, reticulated resist

(burned resist) verify all the recipe parameters are correct and monitor parameters during the process. If problem persists notify NanoFab staff and note it in the logbook.

i) Users are not allowed to VENT or OPEN the Main Chamber Lid. If there is a process or

hardware problem that requires chamber venting notify NanoFab staff to perform a chamber vent sequence.

NANOFAB Research and Teaching Facility

500 South Cooper Street

University of Texas at Arlington

Hazardous Material Gas Release Response Procedure for UTA

Police Department and EH&S Staff

1. When the UTA Police Communications Center receives a Fire Alarm for

NANOFAB, the dispatcher shall check the alarm received and verify if it is a Fire

Alarm or a Gas Detection Alarm.

2. Upon verification of a GAS alarm, the dispatcher shall advise the responding police

units that the alarm is a Hazardous Material Response call and Officers are not to

enter the building for any reason. A Police Supervisor shall be dispatched to the

scene.

3. The Arlington Fire Department shall be dispatched via a 911 call for a Hazardous

Material Gas Leak at UTA NANOFAB building, 500 South Cooper Street.

4. The Responding Officer(s) shall try to respond from the upwind direction. (Look for

wind direction by observing tree leaves, flags or banners in the area.) A wind sock

will be installed on the South East corner of the roof to verify wind direction.

5. The responding Police Supervisor will establish a Command Post at an appropriate

location based on the conditions at the scene.

6. The first responding officer shall verify if the orange strobe lights on the outside of

the building have been activated and listen to the emergency message broadcast on

the outside speakers to confirm a Gas Detection Alarm. Once field confirmation is

made, the responding police units shall set up an inner perimeter. No one is to enter

the building until the arrival of the Arlington Fire Department.

7. Any occupants of the building that may have been exposed to the gas shall be

directed to a designated location (Decon Site) upwind from the building (location to

be determined based on conditions at the time) so paramedics can evaluate their

condition. If any victims are transported to a Hospital, Arlington Fire Department

shall obtain the MSDS for the gas released from the Knox Cabinet on the outside of

the building and provide to the Paramedic. (Not installed yet. Police to provide until

installed)

8. Mr. Jim Florence, the NANOFAB Manager, or a staff member shall brief the Police

Supervisor or first arriving police unit the known facts relative to the incident. The

Officer shall relay the information to dispatch so Arlington Fire Department can be

updated while responding.

9. EH&S staff shall be notified during working hours to respond to the Command Post

with the Police to control the scene until the arrival of the Fire Department. The

Incident Command and Unified Command Systems will be utilized to manage the

incident.

10. After normal working hours the on-call EH&S person shall be notified to respond.