Godin:Protocols/Spin coater

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Spin coater
Spin coater

Laurell WS-400BZ-6NPP/LITE Spin coater

Operation Procedure

WARNING: Your wafer SHOULD NOT be WET or have STICKY CHEMICALS of any kind on the back side. If it is, water and chemicals can get pulled into the vacuum line. This will eventually destroy the tool and may cause problems for the vacuum system as a whole.

Start up:

1) Verify that the vacuum and compressed gas feeds are turned on.

2) Plug in the spinner on the right of the hood. The “Vacuum” warning should be flashing. The “CDA” warning should not be flashing. If it is flashing, the spinner is not receiving sufficient compressed air for some reason.

3) Make sure the waste cup is connected at the back of the spinner to catch any waste.

4) If you are using a hotplate for softbake, get it set to the right temperature.

5) IMPORTANT: If you are using SU-8, line the inside of the spinner lid with tinfoil. Line the spinner bowl with cleanroom wipes. Your goal is to stop SU-8 from getting on the bowl or lid as much as possible.

Programming:

1) Select your assigned letter program. Push “program select” to cycle through programs. (Please do not edit other’s program.)

2) Push “F1” to edit the current program. Edit, add, and delete steps, and edit the step time (in seconds), final spin speed (in rpm) as desired. The “acceleration index”, labeled “ACL” should be set to the default, 015, for all steps. The tool will compute the acceleration rate in rpm/second and display it next to the ACL setting.

For Example;

A program might have 5 steps. This would be a 4 second, 500 rpm “spread” followed by a 30 second 3000 rpm “spin”. Program “A” should be set up like this, only the 3000 rpm number in Step 3 and Step 4 should be changed.

Step 1: Time 2 sec, Speed 500 rpm, ACL 015 Ramps up to 500 rpm in 2 secs.

Step 2: Time 4 sec, Speed 500 rpm, ACL 015 Holds at 500 rpm for 4 secs.

Step 3: Time 2 sec, Speed 3000 rpm, ACL 015 Ramps up to 3000 rpm in 2 secs.

Step 4: Time 30 sec, Speed 3000 rpm, ACL 015 Holds at 3000 rpm for 30 secs.

Step 5: Time 2 sec, Speed 0 rpm, ACL 015 Decelerate to 0 rpm in 2 secs.

3) Once you’ve got your program all set, push F1 to go back to operating mode.

Load a wafer:

1) Set the pins on the wafer alignment tool to your substrate size. Put your wafer on the tool hard up against the stops.

2) Open the lid. Use the tool to center the wafer on the chuck. Push “vacuum” to turn on the vacuum. The wafer should be stuck on the chuck (check it!). The “Vacuum” warning should stop flashing on the front panel.

Static Dispense: It is strongly recommended that before you trust your program, you put a dummy wafer on the tool and run your program without any chemicals to make sure it works as desired!!!! Very Important: If you are using SU-8, polyimide, or some other resist which does not readily dissolve in acetone, then you must line the bowl with cleanroom wipes. You must also very carefully clean up after yourself.

1) Load photoresist onto the top of the wafer. Do not load it so full it flows over the edge. Do not allow any bubbles in the resist. If you get any, try to suck them up with the pipette.

2) Close the lid.

3) Run the program.

Removing the wafer and softbake:

1) If you are working with SU-8, remove the wafer with your SU-8 tweezers. For any other resist, you may remove the wafer with the alignment tool.

2) Put the wafer on a hotplate to softbake. (You must determine softbake times and temperatures from your manufacturer datasheets.)

Clean Up:

Wipe any remaining residue out of the bowl with cleanroom wipes and acetone. Wait for any solvent to drain into the waste reservoir, then remove it and dump it into the solvent waste bottle beside the hood in the lab. Rinse out the waste cup with acetone and isopropanol.

Shutting Down:

1) Unplug the spinner.

2) Turn off the hotplate, if you used one

3) Close the compressed air valve on the wall back of the aligner. The outlet pressure should start to drop.

4) Close the faucet-style vacuum valve on the wall to the left of the hood.

** Let’s try to keep this spinner alive and useful for a long time.

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