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Tylanfga, semi-clean

Operation of tylanfga is very similar to the operation of tylan1-4.

Background

 

Process Capabilities (Cleanliness, Materials, Performance)

 

  • Tylanfga is a semi-clean furnace.  Wafers with deposited  SNF standard metals (Al, Al/Si, Ti and W) from  clean metal deposition tools (gryphon and some semi-clean B tools only) may be processed in tylanfga.

 

Contact List and How To Become a User

Please follow the following procedure to become a qualified user of a tylan furnace;

 

Read all material on the SNF website concerning the specific furnace, including Background, Process Capabilities, Operating Procedures and Process Monitoring.

 

  1. Contact a superuser (link to superusers list) or qualified user of the furnace to arrange to ‘shadow’ them while they use the tool.  The reservation option on coral will show who will be using the tool in the near future.  You are responsible to be with that labmember for the full time they are operating the tool, and it would be intelligent to ask questions and try to become as familiar as possible with the furnace during this ‘shadowing.’  You may have to shadow the superuser or qualified user more than one time.
  2. During the shadowing session you should have the Shadowing Form for the person you are watching to fill out and an Equipment Checklist (see Training Checklist Section of this document).  You should use this checklist to make sure that the tool is completely covered.  You will have to be able to understand each point on it before the labmember notifies the staff responsible for training that you are ready for training.  Both of you must agree that you are ready.  You may have to shadow a labmember more than once.
  3. Contact the staff trainer to arrange for training on the furnace.
  4. If there is a written test for the tool you will need to hand it in to the staff member before training commences.
  5. After training you will be given  provisional qualification status.  This allows you to use the furnace during staffed hours, 0600-1800 Mon-Fri only.
  6. Once a superuser or staff member has watched you and you have satisfactory demonstrated the proper use the tool you will be granted a full qualification to use the tool anytime, 24/7.

 

 Operating Procedures

System Capabilities

 

  • Number of wafers per run: 50 4 inch wafers and/or 25 3 inch wafers.  Partial wafers may be accommodated; please see staff.
  • Wafer thickness: 250 um to 750 um.  Thicker wafers may be accommodated; please see staff.
  • Temperature range: 350C to 600C.  Other temperatures may be accommodated; please see staff.
  • Forming gas at this furnace is 20% H2 in N2.
  • The labmember chooses both the temperature and the time of a furnace run.  Recipes have been written for specific temperatures and a partial listing of recipes is located at http://snf.stanford.edu/Equipment/tylanrecipes/  A full listing of recipes may be found on the disk marked FGA at the Tycom.

 

Cleanliness Standards

 

Substrates allowed; Si, SiGe, SOI and quartz.  No glass or plastic wafers.  Metals must have been deposited in a clean system, such as the gryphon.  No photoresist is allowed.

Wafers should be clean at wbmetal or by using clean quartzware at wbgeneral.  An organic clean such as PRS1000 is sufficient.

 

User Protocol

 

  • These systems tend to be high-use tools, so please honor or remove any reservations you have made.
  • Try keep to a four hour limit per furnace per day during prime-time (Mon-Fri, 0800-1800).  Try to arrange to long  anneals on the weekend or over night.
  •  You may use the reservation if the person who has signed up is not at least cleaning wafers 15 minutes into the reservation.  Please make your best effort to verify the person is not ready to use the system.  Also, if a furnace is not reserved, go ahead and reserve it for your use.

 

Check System Status- Standby Conditions

 

  1. Check the furnace status on coral; is it on shutdown?  Is there a problem message?  Is it enabled by another labmember?  Check out any problems that may have been reported with process or maintenance staff.  Do not use a furnace that has been shutdown.
  2. Enable the furnace.
  3. Go to the furnace and using the STATUS button verify that the system is in ‘Ready’ mode.  You will not be able to load a recipe until ‘Ready’ mode has been achieved.
  1. Look around the furnace deck and adjacent tables for any handwritten notes from previous users of the furnaces.

 

Loading a recipe (program)

 

  1. Furnace programs are written by staff only.  If you need a program that you are unable to find on any of the floppy disks at the Tycom, please ask the responsible staff member to write one for you.
  2. To look at the status of all the furnaces type DI ST SY for DIsplay STatus of SYstem.  To look at a specific furnace use DI ST <furnace number>.  This gives you lots of information; is the furnace in Ready or Run mode?  Temperature of the load, center and source areas of the hot zone is displayed.  Also, gas flows can be seen.
  3. At the Tycom make sure you choose the correct floppy disk.  To verify that the desired program is on the disk, type ‘DI DI’ for DIsplay DIsk.
  4. To examine a program type ‘DI RE <recipe name>’ for DIsplay REcipe.  This is a good time to add up the time of all of the steps to get the total time of the recipe. Don’t forget to add the oxidation time you have chosen in the time variable step or steps.
  5. To load the program type ‘LO <recipe name><furnace number>’ for Load recipe.  You may be asked for one or more time variables and they must be inputted in the format hh:mm:ss.  You will need to specify the colons.
  6. Once all the variables have been loaded, the system will go into compile mode.  This may take a minute or so and the screen should read ’GOOD LOAD’ and ‘TASK COMPLETE’.  If there was an error, an improperly input variable for example, you will still get the ‘TASK COMPLETE’ message.  Check carefully that ‘GOOD LOAD’ has appeared as well.  If it hasn’t, you’ll need to load the recipe again.
  7. A word of warning; once you have loaded a program you will not be able to review the variables.  If there is any doubt in your mind about the correctness of the variable, simply reload the program.
  8. One last thing, you may check the status of the furnaces from outside of the lab by going to: http://171.64.100.113:7116/tylan/tylansummary.html  Every five minutes a 'snapshot' of the furnace status is posted on this site.

Loading wafers onto the boats

 

  1. Push the run button at the furnace control panel –or- at the Tycom type ‘RUN <furnace#>.  This starts the program.  The first step of most programs is to pull the boats out of the furnace at a slow rate.  This takes about five or six minutes to complete, and the cantilever/boat assembly will be hot.  The idle temp of the systems is 800C.  Please be careful around it.  (As an aside, if you are going to use temperature lower than 800C, load the program two or more hours in advance so that the system has enough time to decrease and stabilize the new temp.)
  2. Ideally, we do not want the boats to be out of the furnace for more than 15 minutes.  This is to save wear and tear on the heating elements. They are somewhat difficult to replace.  You will need to calculate the total time of your program and note the time the program was started.
  3. Using the correct tweezers is essential.  For wafers polished on a single side, use the quartz vacuum wands that are provided at the furnaces.  In some cases there is more that one type of wand.  Please make sure that you are using the appropriate to your wafer cleanliness level.  For wafers polished on both sides do not use the vacuum wands- they will leave a scratch mark where they touch the surface.  Instead, use clean non-metal plastic (delrin) tweezers.  They must be cleaned according to; http://snf.stanford.edu/Process/WetProcessing/TweezerCln.html.  Use care with the plastic tweezers when unloading the wafers from the boats- they melt quite easily.  Metal tweezers, even Teflon coated are never to be used to load wafers at any of the furnaces.
  4. By convention, wafers are loaded with the frontside facing the furnace door and with the flats oriented up.  This way if there is a problem with your furnace run information about film uniformity can be given to responsible staff.
  5. After loading the wafers onto the boats, press ALARM ACK to start pushing the boats back into the furnace.  From here on the program is automatic.  This is also the point at which you should note the time of day.
  6. Monitoring the recipe during the run is a good idea.  Make sure that the boats go completely into the furnace before leaving the area.

 

Unloading the wafers and completing theanneal

 

  1. The last step of the recipe is to pull the boats out of the furnace.  The wafers will sit out of the furnace until you give the command to go back into the furnace tube.  So remember to be sure that you are back to attend to the furnace within 15 minutes of the boats coming out.
  2. Unload the wafers after they have cooled enough that they will not melt the delrin tweezers, if you are using them.
  3. Once you have put the wafers into a storage box they are considered dirty and will need to go through a complete  clean if they require another semi-clean process step. 
  4. To end the program and push the cantilevers back into the furnace tube push ALARM ACK.  You will hear an audible alarm.  To stop it, push ALARM ACK once again.
  5. The furnace is now back into the stand by condition and can disable the tool.

 Training Checklist

£ Be familiar with basic equipment description.

 

£ Know temperature range.

 

 £ Be very aware of the cleanliness level of each furnace.

 

£ Know allowable materials for each furnace.

 

£ Know the proper furnace cleans and their time limits.

 

£ Be aware of user protocols.

 

£ Show competency in determining whole system and specific furnace status at the Tycom.

 

£ Know how to check and load a recipe.  Be familiar with the function of each of the steps in a recipe.

 

£ Know how to correctly load wafers using vacuum wand or proper cleanliness tweezers.

 

£Abide by the 15 minute rule.

 

 

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