Approved by Principal Investigator Date: Approved by Super User: Date:

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1 Approved by Principal Investigator Date: Approved by Super User: Date: Standard Operating Procedure BNC Commonwealth Dual Ion Beam Deposition System (CDIBS) Version 2010 February 14 I. Purpose This Standard Operating Procedure (SOP) outlines requirements to be considered by an authorized user of the CDIBS as well as describes the normal operation of the CDIBS and any hazards that may be encountered during normal operation. Finally, the SOP explains how to minimize any hazards and how to respond in an emergency situation. This document is to be reviewed one year from the date of approval or as conditions warrant, whichever is the shorter time period. II. Personnel A. Authorized Personnel: The CDIBS may be operated only by authorized personnel who are fully cognizant of all safety issues involved in the operation of such a device. These personnel are to ensure that the CDIBS is only operated in the manner laid out in this document. To become an authorized user, one must: 1. Complete Environment, Health & Safety (EH&S) training class. 2. Complete BNC Safety Orientation. 3. Read and fully understand the SOP 4. Receive training on the CDIBS by an authorized user. 5. Sign the authorized user sheet to affirm that the above steps have been completed.

2 B. Unauthorized personnel: No unauthorized personnel may enter the BNC clean room facility unless accompanied by an authorized user. All visitors must be briefed on proper safety protocol and must wear appropriate protective eyewear located on the premises. III. Hazards A. Electrical Hazards: electrical shock or electrocution could result from direct contact with high voltage. Such hazards are typically interlocked by the CDIBS system. High voltage RF electrode and conductors are located inside the CDIBS system chassis. In addition, the external high power supply unit has connections behind the power supply chassis. Do not disconnect the external power lines. Use normal precautions with external house (110VAC) and three phase (208VAC) connections behind the CDIBS chassis and service corridor. B. Chemical: Bottled gases are used with the CDIBS. Do not disconnect or tamper with gas lines behind the CDIBS. C. Pressure Hazards: Pressurized bottled and house gases are used with the CDIBS. Do not disconnect or tamper with gas lines behind the CDIBS. Contact lab management for information. D. Other: Optical radiation is generated and emitted through the CDIBS chamber viewing port. Wear protective eye wear is not required when looking through the chamber view port. However, it is a requirement when working within the clean room laboratory. IV. Hazard Controls A. Electrical 1. Enclosures for protection against the high voltages of the CDIBS or high voltage power supply may only be removed after the power supply has been unplugged from the outlets and after following the safety procedures outlined in the safety and operations manual provided by the manufacturer. 2. Only qualified personnel may perform all internal maintenance to the CDIBS and more than one user must be present when performing said maintenance. 3. Every portion of the electrical system, including the printed circuit cards, should be assumed to be at dangerous voltage level. B. Chemical and Pressure Standard Operating Procedure BNC CDIBS 2

3 1. Enclosures for protection against valves and internal gas plumbing may only be removed after the system has been turned off and gases have been valve off and relieved of line pressure. C. Other 2. Only qualified personnel may perform all internal gas maintenance to the CDIBS and more than one user must be present when performing said maintenance. 1. Proper eye protection must be worn at all times in the clean room and while operating the CDIBS. V. Normal Operation A. Inspect all electrical and water connections for damage and connectivity. B. Complete the check-in log. Write in the log book your name, date, and process used or maintenance done. C. Introduction The left side of the system is used for ion milling (etching) to remove material from a wafer. The right side of the system mills a selected target, resulting in sputter deposition on a wafer. The respective target can be selected from one of 4 available or a new target mounted in one of the available four positions. For the ease of maintenance, targets should be changed infrequently. Chromium or Titanium, typically used as an adhesion layer, a masking layer, and conduction layer, is normally installed. Gold is normally installed. Nickel, used along with Chromium and gold for adhesion, is also normally installed. D. Operation of the Deposition (Right) Side In many of the steps given below, the exact order of execution does not matter. However, they are provided as to give the novice user a start. D.1. Sign into the Log Book. Make sure all electrical breakers supplying power to the system are turned on. There is a small switch panel on the front of the system (see Picture). It is labeled Vacuum Pump. Turn ON the vacuum pump switch (the pump should turn on in the service corridor). Standard Operating Procedure BNC CDIBS 3

4 D.2. Turn on the gas supply. The Argon tank is located in the service corridor. Open valve on tank and regulator. The pressure is preset to 4 to 5 PSI such that the flow rate and hence the pressure will be correct during operation. D.3. Close the Cryo main gate valve and Vent the chamber. The system is normally left in high vac (with the cryo pump gate valve open). Close HI VAC (Closing the cryo gate valve) by moving the switch to the center position. The light will turn off and the valve motion operation can be heard. Wait until audible motion has ceased. Turn on the VENT by pushing the switch up, allowing nitrogen to fill the chamber. Wait approximately one minute until the pressure inside reaches atmospheric pressure, allowing the chamber door to be opened. The nitrogen can be left on or turned off while the chamber is open. D.4. Remove Target Lids. Wear gloves when working inside the chamber to keep it clean (skin is oily, salty, and sheds particles). Remove the lids from the targets that will be used. With a screw driver, loosen each of the two clamp screw slightly. Swing the clamps just out of the way of the target. Tighten the clamps back down. Finally, remove the lid. Ensure that target block rotates freely if more than one target will be used. Each target has a number. When viewed from the back side of the chamber where rotation is done, the target in use is at the upper left (which is the upper right when viewed from the door side). Presently target 1 is, Target 2 is Cr, Target 3 is Ni, Target 4 is Au. To rotate the target block, pull the large black knurled knob out about a half inch (pass the shiny positioning stopper), rotate in increments of 90 degrees to arrive at the appropriate target of interest, and push the knob back in. D.5. Mount Wafer on Rotating Stage. Place a wafer on the stage (chuck), holding it so that it does not slide off. Use the four spring clips on the chuck to secure the wafer. Ensure that the clips do not protrude so far Standard Operating Procedure BNC CDIBS 4

5 below the chuck that they interfere with chuck rotation. This can be checked by turning the stage rotation and observing it. Leave the wafer surface upward (at 0 degrees) at this time. Turn on the stage rotation. D.6. Pump the Chamber Down. Before closing the door, check that the stage will not bump the chamber wall. Close the door ensuring that it touches the chamber around the entire perimeter. The O- ring on the chamber door must be flush against the chamber wall. Due to the double hinge design, it may take some force to get the door properly positioned. Turn the nitrogen vent off if it is not already off. Open the roughing pump (Rough) valve (switch up). The light goes on. Let the chamber pump down to just 40 mtorr on the thermo couple gauge (TC1), then close the roughing valve (switch in center). This takes about 2 minutes. Don t leave the roughing valve open below 40 mtorr for very long as back streaming of the roughing pump oil into the chamber can occur. This will be evident if your films will not adhere to the wafers. Open the high vac (cryo) valve (switch up). The light goes on. The pressure on the thermocouple gauge should rapidly fall to near zero. Check the temperature on the cryo pump. It should be around 15K. If not, pumping will be slower and the cryo may need regeneration. Turn on the ion gauge, it is not on already. Degas it for up to 1 minute if desired. Let the chamber pump to below 2x10-5 Torr. This may take about 5 minutes. Record the exact time in the log book. D.7. Set Stage Arm Alignment Move the stage arm such that the vertical mark on center of the window, the left side of the stage, and the vertical mark on the back wall of the chamber are aligned. This centers the wafer over the target. A flash light is needed (alternatively, do it when the gun is on for better lighting). Close the covers on the windows such that the film being deposited does not also deposit on the windows. D.8. Cooling water The cooling water should be on continuously. The valves for the cooling water are located in the service corridor. D.11. Turn on Fans and Gas (Right Side) Standard Operating Procedure BNC CDIBS 5

6 Push the FANS button. This turns on the cooling fans to the deposition gun. The gas controls are located on the chamber front lower panel. There are 6 knobs, 4 toggle switches, and one meter. The meter reads in SCCM. The gas flow controller is setup as follows: Channel A is the main gas flow control from the cylinder. Channel B is the gas directed to the deposition ion gun. Channel C is the gas directed to the etching ion gun. Channel D is not connected. Determine whether you are going to etch only, deposit only, or both etch and deposit. If you already know your exact gas flows from previous work, set them up now. Set your gas flows and flip on the required gas switches as shown in figure above. Select the following combinations: A and B for deposition only, A and C for etching only, or A, B, and C for a combination ion gun assisted deposition. Set the cal/set/read dial knob to SET. Use the respective gas regulator knob for the particular selection to set the flows. Since the chamber is at the scale of 10-5 to 10-7 torr, the chamber pressure should rise rapidly, stabilizing at approximately 3 x 10-4 torr. This should take less than a minute to stabilize. If the chamber does not stabilize, check if the gas cylinder regulator is set to 4 PSI. If not, set cylinder pressure accordingly. Let the gas flow for 3 minutes for the first deposition of the day and 1 minute thereafter. This helps flush out water vapor and other contaminants that would not be desirable in the film. Change the Cal/Set/Read knob to READ for monitoring the respective gas flows. D.12. Ion Gun Operation for Deposition D.12.1 The Cathode Module is a current regulated supply that provides power to the ion source system s cathode filament. The filament, in combination with the anode and chamber pressure, initiates and controls the ion beam current. If the beam current decreases, the cathode inverter must be adjusted to increase the filament current in order to maintain the proper beam current. If the beam current increases, the cathode filament current must decrease. Standard Operating Procedure BNC CDIBS 6

7 D.12.3 The Discharge Module is a voltage regulated supply that provides energy for the ionization process. The ionization process is controlled by the emission of electrons from the cathode filament. The emission is controlled by the cathode filament current. The source of electrons for the emission is the negative terminal of the discharge inverter, which is connected to the center tap of the cathode inverter. The positive terminal of the discharge inverter is connected to the positive terminal of the beam inverter and the ion source system s anode to provide a path for electron flow back to the discharge inverter. If the discharge current decreases, the cathode inverter module must be adjusted to increase the cathode filament current, which will in turn increase the discharge current. D.12.4 The Beam Module is a voltage regulated supply that provides voltage and current for the ion beam. The beam inverter maintains beam voltage; however, the beam current is dependent upon the cathode filament current, as discussed, above under Cathode Module. D.12.5 The Accelerator Module is a voltage regulated supply that provides power to the accelerator grid, which focuses the ion beam. The accelerator voltage is typically set for minimum accelerator current. Consequently, this is the lowest power inverter in the system. D.12.6 The Neutralizer Module is a current regulated supply that provides electron emission (neutralizer emission current) from a hot filament. The emission neutralizes the space charge for the ion beam. As a result, the neutralizer emission current must be approximately equal to the beam current. If the neutralizer emission decreases, the neutralizer module must be adjusted to increase the neutralizer filament current in order to maintain the desired balance between the neutralizer emission current and the beam current. Typical Deposition Gun Readings Magnet Glow Cathode Accelerator Extractor Self Bias Neutralizer 3.2A 3.0A 11.0A 200mA <30mA @300V Off Off D.13. Target Cleaning. The wafer should be still facing up, away from the target, to avoid direct material deposition on the wafer. Stage rotation should be on. Sputter clean the first target for up to 5 minutes, depending on the material and previous use. (Gold does not oxidize and should only have some adsorbed species on it. A 1 minute clean on the gold target is sufficient. Chromium oxidizes rapidly and requires a 3 minute clean. Standard Operating Procedure BNC CDIBS 7

8 D.14. Deposit Film. Rotate the wafer such that it is facing down (tilt 180 degrees). Deposit the desired time then turn the wafer back up (tilt 0 degrees). Make sure that the wafer does not touch the target. D.15. Turn Off the Gun. If necessary, turn down all the settings to zero. Push the GUN button to turn it off. Let the fans run for 10% of the total gun-on time for cooling. D.16. More Depositions As Desired. Rotate to the next target and Deposit per D.14. D.17. Cool, Turn Off the Fans, and Gas. Let the fans run for 10% of the total gun-on time for cooling. Push the FANS button to turn off the fans. Turn off the gas on the regulator switches. The pressure on the ion gauge should rapidly drop and return to the 10-6 to 10-7 torr range. D.18. Turn Off the Stage. Turn off the Stage Switch. D.19. Vent. Turn off HI VAC. Wait for the gate valve to close. Turn on VENT. Remove wafers when vented. D.20. Pump Down the Chamber, Leave un High Vacuum. Close the door, ensuring that it touches the chamber around the entire perimeter. Turn the nitrogen VENT off, it it is not already off Open the roughing pump (ROUGH) valve (switch up). The light goes on. Let the chamber pump down to just below 40 mtorr on the thermocouple gauge (TC1 on the right side rack), then close the roughing valve (switch in center). Open the high vacuum (cryo) valve (switch up). The light goes on. The pressure on the thermocouple gauge should rapidly fall to zero. Leave the system in this state. D.21. Turn off the Gas Supply Close the hand valve on the Argon tank. Standard Operating Procedure BNC CDIBS 8

9 E. Operation of the Ion Mill (Left) Side In many of the steps given below, the exact order of execution does not matter. However, they are provided as to give the novice user a start. E.1. Sign into the Log Book. Make sure all electrical breakers supplying power to the system are turned on. There is a small switch panel on the front of the system (see Picture). It is labeled Vacuum Pump. Turn ON the vacuum pump switch (the pump should turn on in the service corridor). E.2. Turn on the gas supply. The Argon tank is located in the service corridor. Open valve on tank and regulator. The pressure is preset to 4 to 5 PSI such that the flow rate and hence the pressure will be correct during operation. E.3. Close the Cryo main gate valve and Vent the chamber. The system is normally left in high vac (with the cryo pump gate valve open). Close HI VAC (Closing the cryo gate valve) by moving the switch to the center position. The light will turn off and the valve motion operation can be heard. Wait until audible motion has ceased. Turn on the VENT by pushing the switch up, allowing nitrogen to fill the chamber. Wait approximately one minute until the pressure inside reaches atmospheric pressure, allowing the chamber door to be opened. The nitrogen can be left on or turned off while the chamber is open. E.4. Check Target Lids. Wear gloves when working inside the chamber to keep it clean (skin is oily, salty, and sheds particles). Lids should be covering each target. At least check that the selected or exposed target is covered such that sputtered material does not coat it. E.5. Mount Wafer on Rotating Stage. Standard Operating Procedure BNC CDIBS 9

10 Place a wafer on the stage (chuck), holding it so that it does not slide off. Use the four spring clips on the chuck to secure the wafer. Ensure that the clips do not protrude so far below the chuck that they interfere with chuck rotation. This can be checked by turning the stage rotation and observing it. Leave the wafer surface upward (at 0 degrees) at this time. Turn on the stage rotation. E.6. Pump the Chamber Down. Before closing the door, check that the stage will not bump the chamber wall. Close the door ensuring that it touches the chamber around the entire perimeter. The O- ring on the chamber door must be flush against the chamber wall. Due to the double hinge design, it may take some force to get the door properly positioned. Turn the nitrogen vent off if it is not already off. Open the roughing pump (Rough) valve (switch up). The light goes on. Let the chamber pump down to just 40 mtorr on the thermo couple gauge (TC1), then close the roughing valve (switch in center). This takes about 2 minutes. Don t leave the roughing valve open below 40 mtorr for very long as back streaming of the roughing pump oil into the chamber can occur. This will be evident if your films will not adhere to the wafers. Open the high vac (cryo) valve (switch up). The light goes on. The pressure on the thermocouple gauge should rapidly fall to near zero. Check the temperature on the cryo pump. It should be around 15K. If not, pumping will be slower and the cryo may need regeneration. Turn on the ion gauge, it is not on already. Degas it for up to 1 minute if desired. Let the chamber pump to below 2x10-5 Torr. This may take about 5 minutes. Record the exact time in the log book. E.7. Set Stage Arm Alignment Move the stage arm such that the vertical mark on center of the window, the left side of the stage, and the vertical mark on the back wall of the chamber are aligned. This centers the wafer over the target. A flash light is needed (alternatively, do it when the gun is on for better lighting). Close the covers on the windows such that the film being deposited does not also deposit on the windows. E.8. Cooling water Standard Operating Procedure BNC CDIBS 10

11 The cooling water should be on continuously. The valves for the cooling water are located in the service corridor. E.11. Turn on Fans and Gas (Left Side) Push the FANS button. This turns on the cooling fans to the deposition gun. The gas controls are located on the chamber front lower panel. There are 6 knobs, 4 toggle switches, and one meter. The meter reads in SCCM. The gas flow controller is setup as follows: Channel A is the main gas flow control from the cylinder. Channel B is the gas directed to the deposition ion gun. Channel C is the gas directed to the etching ion gun. Channel D is not connected. Determine whether you are going to etch only, deposit only, or both etch and deposit. If you already know your exact gas flows from previous work, set them up now. Set your gas flows and flip on the required gas switches as shown in figure above. Select the following combinations: A and B for deposition only, A and C for etching only, or A, B, and C for a combination ion gun assisted deposition. Set the cal/set/read dial knob to SET. Use the respective gas regulator knob for the particular selection to set the flows. Since the chamber is at the scale of 10-5 to 10-7 torr, the chamber pressure should rise rapidly, stabilizing at approximately 3 x 10-4 torr. This should take less than a minute to stabilize. If the chamber does not stabilize, check if the gas cylinder regulator is set to 4 PSI. If not, set cylinder pressure accordingly. Let the gas flow for 3 minutes for the first deposition of the day and 1 minute thereafter. This helps flush out water vapor and other contaminants that would not be desirable in the film. Change the Cal/Set/Read knob to READ for monitoring the respective gas flows. E.12. Ion Gun Operation for Milling Standard Operating Procedure BNC CDIBS 11

12 E.12.1 The Cathode Module is a current regulated supply that provides power to the ion source system s cathode filament. The filament, in combination with the anode and chamber pressure, initiates and controls the ion beam current. If the beam current decreases, the cathode inverter must be adjusted to increase the filament current in order to maintain the proper beam current. If the beam current increases, the cathode filament current must decrease. E.12.3 The Discharge Module is a voltage regulated supply that provides energy for the ionization process. The ionization process is controlled by the emission of electrons from the cathode filament. The emission is controlled by the cathode filament current. The source of electrons for the emission is the negative terminal of the discharge inverter, which is connected to the center tap of the cathode inverter. The positive terminal of the discharge inverter is connected to the positive terminal of the beam inverter and the ion source system s anode to provide a path for electron flow back to the discharge inverter. If the discharge current decreases, the cathode inverter module must be adjusted to increase the cathode filament current, which will in turn increase the discharge current. E.12.4 The Beam Module is a voltage regulated supply that provides voltage and current for the ion beam. The beam inverter maintains beam voltage; however, the beam current is dependent upon the cathode filament current, as discussed, above under Cathode Module. E.12.5 The Accelerator Module is a voltage regulated supply that provides power to the accelerator grid, which focuses the ion beam. The accelerator voltage is typically set for minimum accelerator current. Consequently, this is the lowest power inverter in the system. E.12.6 The Neutralizer Module is a current regulated supply that provides electron emission (neutralizer emission current) from a hot filament. The emission neutralizes the space charge for the ion beam. As a result, the neutralizer emission current must be approximately equal to the beam current. If the neutralizer emission decreases, the neutralizer module must be adjusted to increase the neutralizer filament current in order to maintain the desired balance between the neutralizer emission current and the beam current. Typical Deposition Gun Readings Magnet Glow Cathode Accelerator Extractor Self Bias Neutralizer 2.0A 3.0A 9.5A 100mA <20mA @300V E. 13. Etch Wafer. Standard Operating Procedure BNC CDIBS 12

13 Rotate the wafer such that it is facing up and to the left (tilt 45 degrees), giving the highest sputter yield. Ion mill (etch) for the desired time, then turn the wafer back up and to the right (tilt -10 degrees) E. 14. Turn Off the Gun. If necessary, turn down all the settings to zero. Push the GUN button to turn it off. Let the fans run for 10% of the total gun-on time for cooling. E. 15. Cool, Turn Off the Fans, and Gas. Let the fans run for 10% of the total gun-on time for cooling. Push the FANS button to turn off the fans. Turn off the gas on the regulator switches. The pressure on the ion gauge should rapidly drop and return to the 10-6 to 10-7 torr range. E. 16. Turn Off the Stage. Turn off the Stage Switch. E. 17. Vent. Turn off HI VAC. Wait for the gate valve to close. Turn on VENT. Remove wafers when vented. E. 18. Pump Down the Chamber, Leave un High Vacuum. Close the door, ensuring that it touches the chamber around the entire perimeter. Turn the nitrogen VENT off, it it is not already off Open the roughing pump (ROUGH) valve (switch up). The light goes on. Let the chamber pump down to just below 40 mtorr on the thermocouple gauge (TC1 on the right side rack), then close the roughing valve (switch in center). Open the high vacuum (cryo) valve (switch up). The light goes on. The pressure on the thermocouple gauge should rapidly fall to zero. Leave the system in this state. E. 19. Turn off the Gas Supply Close the hand valve on the Argon tank. Standard Operating Procedure BNC CDIBS 13

14 VI. Emergency Procedures A. CDIBS accidents: Notify lab management and PI immediately. B. Power outage: If there is a power outage, turn off the CDIBS per the CDIBS shut down procedure to avoid a hazardous situation when power is restored. Standard Operating Procedure BNC CDIBS 14

15 Authorized Users I have read and understood the Standard Operating Procedures for CDIBS Name (print) Signature Date PI Initial Standard Operating Procedure BNC CDIBS 15

16 Appendix A In case of medical emergencies, consult lab safety protocol or lab safety plan. In the event of a CDIBS accident, follow the procedure below: 1. Ensure that the CDIBS is shut off. 2. Provide for the safety of the personnel (first aid, evacuation, etc.) as needed. 3. Obtain medical assistance for anyone who may be injured. UC Optometry Clinic (Normal Hours) UC Optometry Clinic (24 Hour Emergencies) University Health Services (Emergency) Ambulance (urgent medical care) If there is a fire, pull the alarm, and contact the fire department by calling Do not fight the fire unless it is very small and you have been trained in fire fighting techniques. 5. Inform the Office of Environment Health, & Safety (EH&S) as soon as possible. 6. During normal working hours, call the following: EH&S Office BNC Safety Officer EH&S Health & Safety Manager After normal working hours, call to contact the UC Police Department who can contact the above using their emergency call list. 7. Inform (PI NAME) and the BNC safety officer as soon as possible. If there is an injury, (PI NAME) will need to submit a report of injury to the Worker s Compensation Office. 8 After the incident, do not resume use of the CDIBS system until the lab manager and EH&S has reviewed the incident and approved the resumption of research. Standard Operating Procedure BNC CDIBS 16