Nanofabrication Facility: PECVD SOP Rev. 00, April 24 - 1
Contents
1. Press Unload Wafer to remove your sample The unloading step is very similar to step 2 Remove your sample once the load lock reaches atmosphere Repeat the process steps as many times as needed ye Nanofabrication Facility PECVD SOP Rev 00 April 24 Note it is possible and is not unlikely with a small sample that during the loading and unloading stages the sample will flip onto its other side Again the superuser suggests using a cleaved 100 mm wafer to create a small sample holding cavity to alleviate this problem Shut Down l 2 3 Make sure that the susceptor is flush with the loading fork guide Close the DES valve if you used it please close DELICATELY It closes CLOCKWISE Press Load Wafer The wafer is left inside the growth chamber to reduce the load on the robotic arm It also helps if the next user wishes to preheat the susceptor before his her growth etch Press Stand By 5 Make sure that the system properly makes it through its purge vent sequence Exit the clean room enter the chase and turn off the gases used Typically Nitrogen is always left on as many other processes in the clean room use it Manual Recovery In the event of a mechanical failure or some other abnormal operation it may be required to enter the maintenance mode In this mode the user can operate many of the individual steps that are normally all handled within a single process step The following outlines recovery of the ro2. appears refer to the end of this SOP on recovery Nanofabrication Facility PECVD SOP Rev 00 April 24 e The PECVD uses a combination touch screen and keyboard interface Most operations are conducted with the touch screen and any occurrence of operation in this guide will be in reference to the touch screen unless otherwise noted Start Up 1 Before entering the clean room the gasses used for an intended process must be turned on from the master valves located in the cleanroom chase area Access from room 444 All of the gasses except ammonia are in large cylinders located against the clean room wall adjacent to the PECVD al Ammonia is stored in the vented gas cabinet next to the cylinders AP Each gas is turned on from either a main valve metallic knob on the cylinder itself and or from exit valves on the downstream side of the pressure regulators Nanofabrication Facility PECVD SOP Rev 00 April 24 Carbon Tetrafluoride CF4 Oxygen O2 Nitrogen N2 and Nitrous Oxide N20 are accessed in this manner Nitrogen should always be on for any process Ammonia NH3 can be turned on inside the vented cabinet with its own main valve 2 The DES is opened inside the cleanroom in the black gas distribution cabinet in back of the unit Open it COUNTER CLOCKWISE 3 If CF is being used for your process check that the release valve is closed and the toggle valve is open They should be located behin
3. Files menu Nanofabrication Facility PECVD SOP Rev 00 April 24 6 Record your parameters and sample information in the logbook as necessary Refer to previous entries as a guide 7 Once you are satisfied with the parameters let the system equilibrate to those parameters First allow the chuck to reach the temperature specified The time for this can vary from about an hour when heating up the chuck to hours for cool down NB the temperature read is that of the chuck the graphite susceptor itself will require some time to reach the same temperature Once the temperature reaches the desired level press Vacuum off opens the valve to the pump Pressure off turns on regulation of the butterfly valve and Gas off turns on the gas flow Each button when depressed turns green and displays on instead of off Let the gas come to the desired pressure 8 Once the gas flow is regulated press RF off to ignite the plasma Note the step time counter Press RF on to turn it off once the timer reaches the desired time Press Gas on to turn off the gas flow Let the chamber evacuate until the pressure reaches equilibrium and press Next Step if required Repeat this step as needed 9 Once all steps have been processed press Pressure on and Vacuum on Press Exit to return the to the Main Menu 10 Once exited you are returned to the Main Menu Let the chuck cool down as necessary
4. Nanofabrication Facility PECVD SOP Rev 00 April 24 Author Charlie Yao amp Mario Beaudoin Email charlieyao egmail com Beaudoin physics ubc ca Phone 604 822 1853 MB Purpose This document outlines the standard operation for the Trion Plasma Enhanced Chemical Vapour Deposition PECVD device located in the AMPEL clean room It is written with respect to typical usage and does not attempt to describe every operation available It also describes basic failure mechanisms that may occur during operation Only qualified users and superusers are allowed to operate this equipment Relevant Literature e TRION User s manual e J Micromech Microeng 14 2004 317 323 e Journal of Non Crystalline Solids 338 340 2004 76 8 e Materials Letters 54 2002 102 107 e Robin Farnworth and Michael Musson Optimization of Nanoporous Via Hole Membranes for Micro Electro Mechanical Systems MEMS Engineering Physics 479 project number 0460 under the supervision of M Beaudoin Available at www ampel ubc ca nanofab Procedure Foreword e Be familiar with the reactants and products of the process by consulting the MSDS e Be familiar with safety warnings and alarms should a serious malfunction occur i e major gas leak e In addition to the literature consult a user who s familiar with the process intended If none exist consult a superuser should he have any concerns e Inthe event of a system crash where the Manual Recovery Panel
5. Processing 1 Press the Files button to open a menu for selecting the desired recipe It is important to load the correct settings first to allow the PECVD to equilibrate the temperature as soon as possible Once the desired process is loaded it should appear in the top right of the display under Current Recipe Should you wish to create a new process file refer to step 5 before proceeding to step 2 2 Press Unload Wafer This should bring up the Wafer Unload Sequence and describe the unloading process as it occurs The unloading process will finish with nitrogen venting the load lock to bring it to atmosphere The LCD screen should display when the exchange chamber reaches atmosphere and it should be accompanied with a hissing sound from the lid Open the lid at this point and hit OK When the main menu reappears this button will disappear and a Load Wafer button will appear 3 Place your sample in the center of the graphite susceptor n l nT The susceptor is designed for 100 mm wafers if your sample is much smaller a good trick is to use the _5 Nanofabrication Facility PECVD SOP Rev 00 April 24 cleaved 100 mm wafers available in the cleanroom shelf and specifically marked for PECVD use Ensure that the disk is flush with the back of the arm Check that the large O ring seal is still seated properly If you are concerned about the vacuum discuss the appropriate application of vacuum grease with a superuser C
6. botic arm specifically in loading and unloading 1 To open the Manual Recovery Panel directly press Maintenance in the main menu window A keypad will pop up prompting you to enter a password The superuser should give the password to you when you get qualified to use the machine After the password press Manual Transport The Manual Recovery Panel will pop up by default if there s a malfunction in the device 2 There is no set of steps that completely outlines what to do at any point the machine may have crashed at any number of steps What s important is to understand the steps the machine goes through assess its current state and activate the necessary steps for recovery The following list outlines normal operation with loading and unloading of the chuck Nanofabrication Facility PECVD SOP Rev 00 April 24 oS The robotic arm is retracted with the chuck on the arm and the lid down The exchange chamber is at atmosphere the main gate valve is closed and the pins are retracted Evacuate the exchange chamber by pressing load vacuum Open the main gate valve NB the main gate valve should only be opened if the growth chamber and the load lock are at comparable pressures for typical operation the growth chamber is evacuated and the gate valve should only be opened if the load lock pressure is below 700 mTorr note the m for millitorr 4 Extend the robotic arm 5 Lift the pins to lift the susceptor fr
7. d the PECVD and are a pair of brass valves connecting white 1 4 tubes Nanofabrication Facility PECVD SOP Rev 00 April 24 These valves are normally left in this configuration 4 Upon entering the clean room and accessing the PECVD the user should note that it s currently on Stand By mode Press Cancel to exit Stand By mode The PECVD will go through its own start up process 5 Once the PECVD has finished its start up process an operational main menu should appear with eight buttons and a blank space for a 9 to the middle left he carbon disc should still be in the growth chamber and the arm retracted in the load lock verify by looking through the glass port of the lid to the load lock The centre button should display Unload Wafer This button will disappear and a Load Wafer button will appear in the middle left when the carbon disc is in the load lock From left to right top to bottom the buttons are as follows Files Manual Process Control Automatic Process Control Load Wafer Unload Wafer Stand By Hardware Setup Exit Maintenance Should the disc be on the arm and the Load Wafer button be present rather than the Unload Wafer it implies a previous user did not shut down the system properly and is unnecessarily putting stress on the robotic arm Your process may continue as normal although the first few steps in processing will not be applicable Nanofabrication Facility PECVD SOP Rev 00 April 24
8. lose the lid 4 Press Load Wafer This should bring up the Wafer Load Sequence and describe the loading process as it occurs Be aware of any irregular sounds that might indicate an improper seal on the lid Press Cancel on the process should any reverberating sound occurs that might indicate an overtaxed pumping motor Check the seating and lubrication of the O ring and the action of the lid and repeat this step Should problems persist contact a superuser Under normal operating conditions the load lock should reach 750 mTorr in less than a minute 5 Press Manual Process Control to bring up the process control menu Do not use Automatic Process Control as there are bugs that affect the process In this control menu you can change parameters to tailor to your specific process or define your own process completely For each parameter there are two displayed numbers a parameter set and a parameter read The parameter set displays the current value which the system 1s trying to achieve the parameter read 1s the current measured value of the parameter To change any setting press the desired parameter set and enter in new values The next step and previous step buttons at the bottom right of the screen allow you to cycle through steps and define the values for each parameter per step You can save the file under a new name in the Files menu accessed from the bottom of the screen You can also retrieve other recipe files from the
9. om the loading fork 6 7 8 9 Retract the robotic arm Home the robotic arm Lower the pins to lower the susceptor in position on the growth chamber chuck Close the main gate valve 10 Run processes Exit manual transport mode and proceed through main menu 11 Raise the pins to raise the susceptor above the chuck NB otherwise the loading arm would collide with the susceptor and push it against the back of the growth chamber this would force an unwelcomed vent of the growth chamber and could also create damage to the forks susceptor chuck or other features in the growth chamber 12 Make sure the load lock is under vacuum 1 e 700 mTorr or less 13 Open the main gate valve 14 Extend the arm 15 Lower the pins to lower the susceptor on the loading arm fork 16 Retract the arm 17 Home the arm 18 Close the main gate valve 19 Bring load lock to atmosphere by pressing vent load Nanofabrication Facility PECVD SOP Rev 00 April 24 It is up to the user to identify in which step the malfunction occurred and to identify the course of action given these normal sequence of steps Note that manual operation does not change the main menu status Thus if the user manually loads the chuck and goes back to the main menu it will still display Load Wafer and not display Unload Wafer 10
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