Standard Operating Manual - PDF Free Download

Contents 1. Picture and Location 2. Process Capabilities 2.1 Cleanliness Standard 2.2 Possible Sputtering Materials 2.3 Process Specification 2.3.1 What the ARC12M Sputter Can Do 2.3.2 What the ARC12M Sputter Cannot Do 2.4 Sputtering Process Useful Information 3. Useful Information to Work in NFF 3.1 Emergency Responses and Communications 3.2 Become a Qualified ARC12M Sputter User 4. Operation Safety and Rules 4.1 Operation Safety 4.1.1 General Safety 4.1.2 Equipment Safety 4.2 Operation Rules 5. System Operation 5.1 ARC12M Sputter System Description 5.2 Initial Status Check 5.3 Initial System Check 5.3.1 Software Startup 5.3.2 System Startup 5.4 Preparation before Sputter Process 5.4.1 RF Power Supply ON 5.4.2 Targets Check 5.4.3 Targets Change 5.4.4 Samples Loading 6. ARC12M Automatic Operation 6.1 Recipe Setting 6.2 Automatic Sputter Process 6.3 Equipment Limitations 7. Process Recording during Process 8. Clean Up 9. Check Out Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 2

ARC12M Sputter System 1. Picture and Location Fig.1 ARC12M Sputter system The ARC12M Sputter system is located at NFF Phase II cleanroom, Room 2240. 2. Process Capabilities 2.1 Cleanliness Standard ARC12M sputter is classified as Non-Standard equipment. 2.2 Possible Sputtering Materials Metal materials listed in our website Semi-conductor materials listed in our website Dielectric materials listed in our website Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 3

2.3 Process Specification 2.3.1 What the ARC12M Sputter Can Do Up to three pieces of 4 inches full silicon, glass or quartz substrates. Up to two pieces of 4 square glass substrates. Small samples can be process by fixing on a substrate. Masking material: Photoresist is allowed 2.3.2 What the ARC12M Sputter Cannot do Substrate that generate particles during sputtering process. Substrate that cannot sustain in sputtering temperature. Substrate that contains harmful substances. Gold film sputtering over 5000A is not allowed. Other metal films sputtering over 5000A is approved on request. Dielectric films sputtering over 500A is approved on request. Target contains harmful materials. 2.4 Sputtering Process Useful Information Typical film uniformity is over 10% for 3 wafers sputtering at the same time. However, a better uniformity will be achieved if only one wafer placed at the center of the substrate holder. Typical sputter rate for metal film is over 50A/min. Typical sputter rate for dielectric material is less than 20A/min. Therefore we do not encourage user to sputter a dielectric film over 500A. As the thermal conductivity of dielectric material target is poor, user must pay special attention to sputter dielectric material. In order not to overheat the target, no more than 5 minutes process time per run, and 10 minutes cool down time is required between run. Typical dielectric material targets are fragile and break easily; therefore user must handle it carefully. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 4

Typically, reactive gases O2 or N2 will be added with Argon for sputtering dielectric material. 3. Useful Information to Work in NFF 3.1 Emergency Responses and Communications In case of emergency issues, please contact NFF staffs, Preason Lee Deputy Safety office (x7900), CK Wong senior technician (x7226) In case of technical help, please contact NFF staffs, CK Wong senior technician (x7896) Casper Chung technician (x7896) Brial Kwok technician (x7896) 3.2 Become a Qualified ARC12M Sputter User Please follow the procedures below to become a qualified user of the ARC12M sputter: Read all materials provided on the NFF website of the ARC12M. Request ARC12M operation training and examination online. 4. Operation Safety and Rules 4.1 Operation Safety 4.1.1 General Safety ARC12M user must familiar themselves with the following general safety issues: Location of emergency exits and assembly points Procedures for obtaining first aid assistance must be known. Various alarm sounds and emergency call procedures must be known. 4.1.2 Equipment Safety ARC12M user must be aware themselves of the following equipment safety issues: In emergency when using the equipment, please push the emergency power button (Fig. 2) to interrupt the equipment power, and report to the NFF staffs immediately. DO NOT attempt to resume the equipment on before the problem is solved. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 5

If the equipment fails while being used, never try to fix the problem by your own, please write down the alarm information and report to NFF etching module staffs. Alarm/warning message will be displayed in the control screen (Fig.3). DO NOT attempt to resume the equipment on before the alarm/warning message is verified. Be careful to the components of the equipment, which RF radiation and high temperature hazard. Be careful to the base compartment of the chamber, it involves electric power, electrical shock will be result. 4.2 Operation Rules Do not operate the equipment unless you are properly trained and authorize to operate the equipment. Reserve the equipment in NFF website in advance. Reservation will be forfeited if user never shows up and check-in within half of the session time and it may cause a $200 penalty. Fill all the details of the log-sheet attached, i.e. date, name, project number, email, project details, material Do not leave an on-going sputtering process unattended. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 6

5. System Operation 5.1 ARC12M Sputter System Description The ARC12M is a table top thin film deposition system that fully controlled by processor. It consists of three planar magnetron sputtering guns with 2 diameter targets; one DC and one RF power supply that can be used to co-sputter two kinds of material at the same time. In addition a turbo molecular pump is installed to achieve a high vacuum pressure of 10-5 Torr. Typically, Argon gas is used for metal sputtering, but it also equipped with O2 and N2 gases for dielectric reactive sputtering process. 5.2 Initial Status Check Users are required to do the following checks before doing the sputtering process: Please check the equipment status from the shutdown notice board in the NFF reservation website. If the equipment has been reserved, then check the user name and project number that displayed on the dedicated LCD screen are correct (Fig. 4). Please check-in the reserved equipment on your own within half of the session time. To do the check-in, please scan your NFF access card over the card reader attached. After checked-in the equipment, the red LED on the card reader will be ON. If you are failed to do the check-in, there is an interlock, and you cannot operate the equipment normally. Before operate the equipment, make sure you have read and ready to fill the details of the log-sheets attached. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 8

Fig.4 Reservation and Equipment check-in status LCD 5.3 Initial System Check Visual check any water leakage from the equipment. Check any abnormal sound coming from the equipment. Please turn on the CRT display if necessary. Check the ARC12M software is ready for use. If the software is not start up, please follow the details below to start it. 5.3.1 Software Startup Power on the system computer. Types ARC in the DOS prompt to run the software (Fig.5). A main menu screen will be displayed after system self-checking (Fig.6). Fig.5 software start up Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 9

Fig.6 Main menu screen 5.3.2 System Startup To start up the system, select Manual process menu in the main menu screen (Fig.6). In the Manual Process Menu, type A to enter a Manual Sputter Mode screen (Fig.7a&b). Fig.7a Manual Process Menu Fig.7b Manual Sputter Mode control screen In the manual sputter mode screen, press M to turn on the mechanical pump Then, 10 seconds later foreline valve can be turn on by pressing F5 key (Fig.7b). After that, turbo molecular pump can be start by pressing T key (Fig.8). Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 10

Fig.8 Turbo molecular pump ON Fig.9 Rough valve ON When the turbo molecular pump is running at full speed, the turbo pump ON indicator will become green in color. Otherwise, it is yellow in color during acceleration (Fig.8). Turn off the foreline valve by pressing F5 when the turbo pump is in full speed. Then turn on the rough valve by pressing F4 to evacuate the chamber (Fig.9). Wait the chamber roughing pressure reach 1.5x10-1 Torr (Fig.9). Turn off the rough valve F4, and turn on the foreline valve F5 again. Finally, turn on the gate valve by pressing F6 key (Fig.8). Now the system is ready. Fig.10 System pumping ready status 5.4 Preparation before Sputter Process You are advised to do the following steps before start running the sputter process. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 11

5.4.1 RF Power Supply ON Check the RF power supply and matching unit power button with green labels are clicked ON (Fig.11). Fig.11 RF supply and matching unit power button. 5.4.2 Targets Check Check the name plate that located in front of the power supply and confirm the name of targets that already mounted on each sputter guns are desired material (Fig. 12). Normally, station 1 is fixed for Nickel target, and special approve should be requested for changing target in station 1. Other targets can be mounted on station 2 or station 3. For gold/platinum target, user must write down the weight of the target before and after process on the logbook. If user failed to do this, we will charge you the weight differences of the gold target. To check the weight of the gold/platinum target, use the electronic scale provided. Fig.12 target materials name plate holder Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 12

5.4.3 Targets Change If user needs to change target, please vent the chamber back to atmosphere pressure. To do chamber vent, press F6 key to shut off the gate valve. Then press V key to vent the chamber (Fig.13). Fig.13 Chamber pressure display and vent valve status Wait until chamber pressure approaches 7.6x10 2 Torr shown in the pressure bar (fig.13) and hear the whistle sound from the chamber. Then open the chamber top plate where targets are mounted (Fig.14). Make sure the chamber top plate is fully opened, and avoid it suddenly falls off. Turn off the venting gas by pressing the V button again. Fig.14 Chamber top plate opening. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 13

Confirm the target station number which target is going to change. Use appropriate screw driver or allen-key to remove the shutter (Fig.15). Fig.15 Shutter removal Slightly loose four bolts that fasten the target anode shield and twist it. Then, the shield can be lifted off. (Fig.16). Fig.16 Target anode shield removed Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 14

Slightly loose the four bolts that fasten the target clamping ring and twist it. Then, the ring can be lifted off and target can be removed (Fig.17). However, be careful the target will be dropped once removing the target clamp ring. Fig. 17 Target removal Take out the needed target from the target box (Fig. 18). Then, change the material name plate that magnetic stick on the name plate holder (Fig.12). Fig.18 Target box Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 15

Please be reminded some of the targets are fragile and break easily, user must handle it carefully, otherwise we will clamp you a new target if damage. Put the needed target onto the electrode, mount back the clamping ring and target shield. Make sure the target is centered in the ring, and fasten all the bolts evenly. Then, mount and tighten the shutter. Check the shutters are mounted in position by pressing function keys F1, F2 or F3 ON and OFF according to target 1, 2 or 3 (Fig.19). If the shutter is opened, then the button will become green in color. If the shutter is closed, then the button will become red in color (Fig.19). In case the shutter is free running, the machine will be interlocked, please contact NFF staff to fix it. Fig.19 Shutter opening and operation screen 5.4.4 Samples Loading Place the samples on the rotatable turn table (Fig.20). Check the rotate function of the turn table by pressing the R button, and stop the rotation by pressing R again. The rotation status can be observed in the screen (Fig.20). Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 16

Fig. 20 Rotatable turn table and operation screen Once the turn table is free running, the process will be continuous, and the resulting film uniformity will be affected. So, please monitor the rotation status from time to time during process and contact NFF staff to fix it if required. Close the chamber top plate. Then pump down the chamber again by using the F4, F5 and F6 buttons according to section 5.3.2. The system is now ready. 6. ARC12M Automatic Operation 6.1Recipe Setting To set a recipe and run an automatic process, users are required to click ESC key back to the main menu (Fig.6), and then enter the Automatic process menu (Fig.21). In the Automatic process menu, users are required to set and check the required process data. Details of each item will be described in the following: Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 17

Fig.21 Automatic process menu dc Output power If DC power is required, scroll down to the DC Output Power bar, and click <Enter> to the data input window. Then, input 100W DC power according to the source 1, source 2 or source 3 (Fig.22). After power set, ESC key can be used to exit the data input window. If more than one source will be use, then value for each source can be set and display separated by slashes. Typically the DC power we set is 100W. We never encourage user set too high or too low power, otherwise the DC power supply may be damage or plasma cannot run stable. rf output power If RF power is required, scroll down to the RF Output Power bar, and click <Enter> to the data input window. Then, input 120W RF power according to the source 1, source 2 or source 3 (Fig.22). After power set, ESC key can be used to exit the data input window. If more than one source will be use, then value for each source can be set and display separated by slashes. Typically the RF power we set is 120W. We never encourage user set too high or too low power, otherwise the RF power supply may be damage or plasma cannot run stable. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 18

Fig.22 DC output power and RF output power setting. etch output power This system do not support the etch function, so user is not required to set this parameter. source order Source order is the sequence in which the system will turn on each gun. However, no matter what the sequence is, for every parameter line in the menu, the first number always corresponds to gun 1, the second to gun 2, and the third to gun 3 (Fig. 23). For example, if the source order sequence was RF3/DC2/DC1 and the output power was set at 50/100/150. Then, source 3 would fire first at RF 150W, source 2 would fire second at DC 100W, and source 1 would fire last at DC 50W (Fig.24). For all sequential runs, each source in the sequence will be separated on the menu line by slash. If less than three guns are to be fired, N denotes no action. For example, 1/2/N means to run gun 1, and then run gun 2. However, sources can be run simultaneously will be separated by the & symbol, so 1&2 would run gun 1 and gun 2 together, while 1&3/2 would run gun1 and 3 together, followed by a run of gun 2. If co-sputtering process is required, then two power supplies combination must be selected in the source sequence window for the first source (Fig.24). However, in our system, we only have one DC power supply and one RF power supply, so co-sputtering of two di-electric materials is not allowed. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 19

Iterations and delay The number of iterations for a process run can be selected between 1 and 99 (Fig.25). Then the delay time is the amount of time after iteration starts before the next begins. Fig.25 Iterations and delay input window. shutter delay Shutter delay is the amount of time to wait after the plasma has been ignited before moving the shutter (Fig.26). The shutter delay is useful for pre-cleaning targets before coating. Fig.26 Shutter delay input window. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 21

method of termination The method of termination is the method that ARC uses to determine when to turn off a gun. The termination parameters input order is Stage/Source1/Source2/Source3 (Fig.27). Please be reminded if you are going to deposit a film over 2000A; make sure the target condition is good enough to do such a long time process, otherwise the electrode will be damage if the target is run out. Please be reminded if the total sputter process for metal film is longer than 15 minutes, then the whole process must be separated into iterations. However, if the total sputtering process time is longer than 30 minutes, then iteration is not a suitable termination method. Therefore, user must separate the process into a few sessions, and at least 15 minutes cool down time must be inserted in between, otherwise the target may be over heated and damaged. A new target will be clamped to the user who did not follow this instruction. For sputter dielectric film, the thermal conductivity of dielectric material target is poor. In order not to overheat the target, no more than 5 minutes process time per run, and 10 minutes cool down time is required between run. Fig.27 Termination time set point windows. Vent If vent is selected, the process will turn off the shut-off valve and vent the chamber to atmosphere at the end of run. However, the default vent setting is No. Base pressure The base pressure is the pressure that the chamber must be evacuated before process gas backfilling the chamber (Fig.28). The default base pressure set is Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 22

0.0104 mtorr; typically it takes more than one hour to reach this pressure depends on the chamber and substrate condition. In order to reduce the pump down time, make sure the substrate is well baked. In addition, samples with organic material that trap gases will cause longer pumping time. However, the lower base pressure it achieved, then the better film quality you will get. Fig.28 Base pressure set point window gas backfill pressure The operating pressure, which should be set as low as possible without risking of plasma shutting off (Fig.29). The system usually runs best between 3~8 mtorr, as it varies for different materials. Typically, soft metals are easier to run at low pressure than hard metals, and dielectric materials require more gas than hard metals. Default backfill pressure value is 3mTorr. However, the lower process pressure used, then the better conductivity of the metal film sputtered. Fig.29 Gas backfill pressure set point window Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 23

Plasma ignition pressure This is a separate pressure from the operating pressure (Fig.30). The reason is that some materials are difficult to start at low pressure, but a lower pressure makes better coatings. Therefore, ignition pressure is a step inserted to set pressure higher than the normal operating pressure in order to ignite the plasma successfully. But, it will lengthen the time of a process run because a gas stabilization period is required between the time of the plasma ignition on and the shutter moving. Fig.30 Plasma ignition pressure set point window Gas channel selection User is not required to make this selection. mass flow ratio Back fill pressure is regulated by the mass flow controllers (MFCs) equipped in the system. The gas is always controlled by the pressure and not by flow. Normally, argon gas is used for most kind of metals or dielectric materials sputtering process. But, some of the materials require reactive gas sputtering instead of argon gas sputtering. Therefore, nitrogen or oxygen is required together with the argon gas for the sputtering process. For example, in this case where argon and oxygen are used, if the argon is set for 80% in mass flow ratio window, then the oxygen must correspondingly 20% (Fig.31). In our system, the gas channel 1 is set default for argon gas, and gas channel 2 can be nitrogen or oxygen. However, if gas channel 2 is being used, turn on the gas selection switch to nitrogen or oxygen, which located at the back of the system (Fig.32). Then, turn on the gas inlet switch to the MFC 2 which located behind the MFC2 (Fig.33). Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 24

Fig.31 mass flow ratio set point window Fig.32 Nitrogen/Oxygen gas selection switch Fig.33 Location of turbo pump, pressure gauge, MFCs and shut off switch. Target materials User is not required to set this parameter. Tooling factor User is not required to set this parameter. Heater temperature User is not required to set this parameter. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 25

stage rotation The rotation speed can be set from 5-40 rpm, and the default speed is 8 rpm. When all these parameters have been set, then the process can be start by clicking on the start bar or A key. Finally, the automatic process window will be displayed. 6.2 Automatic Sputter Process The automatic process sequence is 1) base pressure, 2) gas backfill, 3) iteration delay, gas stabilization, shutter delay and sputter process iteration starts, 4) process completed In the automatic process window, the chamber base pressure set point must be reached before the automatic process starts. The chamber base pressure can be observed in the pressure bar displayed (Fig.13) Once the base chamber pressure reached, then according channel gases will be backfill to the chamber (Fig.34). Typically it takes few minutes to achieve the plasma ignition pressure. Fig34. Backfilling chamber screen The next steps are iteration delay and gas stabilization. These steps are mainly require for plasma ignition and target cleaning, it involves: - Turn table rotation. - Shutter open. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 26

- Minimum level power ramp up, ~30W. - Shutter close (Fig.35). - Once the shutter close, pressure will be re-adjust to the chamber backfill process pressure, and source will ramp up further to 100W for cleaning (Fig.36). Fig.35 Shutter closing Fig. 36 Shutter delay and target cleaning - Wait 60s shutter delay and backfill pressure stable. - Shutter will be open again for film sputtering. However, during shutter opening, the plasma may be fluctuate due to the gas flow coming out from the electrode will be deviated until the shutter is completely open. Please be reminded if RF sputtering is employed, user must pay special attention to the shutter opening step, and risking of plasma shut-off due to the gas flow deviation. Also, typically RF reflected power should be less than 5% of the forward power, it can be observed from the RF power supply unit or bar chart of the screen (Fig.37& 38). Excess RF reflected power will cause RF power supply damage. However, the power value displayed on the screen has bit differences to display on the power supply due to the signal synchronization error. Once the power is stable at the set point, then sputtering iteration start. When it starts, the plasma light (Fig.39) can be observed through the view port glass. However, there is a shutter on the view port glass, please use the magnet provided to turn it open. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 27

Once the process completed, then a process completed screen will be displayed (Fig.40) Fig.40 Process completed screen However, if the automatic process is terminated due to any error, then process completed with error will be displayed (Fig.41) Fig. 41 Process completed with error screen During the automatic process running, it can be terminated anytime by clicking the ESC key. To vent the chamber and get back the samples, please follow the chamber opening procedures (section 5.4.3). Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 29

However, in order to avoid thermal expansion or cracking of the target, please vent the chamber at least 15 minutes after the sputter process. If user fails to do this and the target was damaged, then a new target will be clamped to the user who did not follow this instruction. Pump down the chamber again according to the operating procedures section 5.3.2. 6.3 Equipment Limitations ARC12M is old version equipment, and it is unavoidable to have various kinds of hardware problems. In the following, it will summarize the possible hardware problem that may occur, and user must pay attention to it: Set screws to hold the shutter loose, then the shutter cannot run properly. To minimize this happen during process, check the shutter open/close status when loading samples or check it through the viewport once the plasma ignited. Substrate holder is not running. To minimize this happen during process, check the substrate rotation status when loading samples or check it through the viewport once the plasma ignited. RF unstable during shutter opening for process. To minimize this happen, check the target shield and target clamp ring is clean during target change. RF cannot be ignited. To avoid this happen, use higher process pressure, but the film quality will be degraded. If the above situation occurs, then user can write down in the log sheet, and report to NFF technicians for maintenance. 7. Process Recording during Process Please be reminded you are required to fill all the details of the log sheets. If users fail to do this, a punishment will be given. Write down any problems or comments in the log sheets Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 30

8. Clean Up Clean up the area Return screw driver, allen keys, magnet to their proper locations. Return targets to the target box. Make sure the target name plates are correctly labelled. Switch off the nitrogen or oxygen after reactive sputtering process. 9. Check Out Check out the equipment immediately after use. Copyright 11.2015 by Hong Kong University of Science & Technology. All rights reserved. Page 31