Clean Room Rules and Procedures

The goal of a clean room is to control dust below some level to improve yield in making small scale lithographic features. For this reason, the type of clothing worn, items brought in to the room, and procedures followed in the room must be tightly controlled. Failure to follow the procedures below will result in loss of clean room privileges.

1. Before entering the clean room, you must be an authorized user. This involves notifying the lab coordinator that you will be receiving training in the use of the room, going through training, and then letting the coordinator know when training is complete so that your name can be added to the users list. Taking the processing course, 435/535, qualifies as training.
2. Proper clean room clothing must be worn by everyone who enters the room. Clean room clothing is put on and removed in the entry area to the clean room. To keep the clean room clothing from becoming contaminated with dust and dirt, clothing should not leave the clean room entry area. We allow lab coats and hair nets to leave (keep them off the floor!), but booties must stay in the clean room entry area and not be used in the main lab. If there is a shortage of clothing, contact the coordinator.
3. Proper clothing includes:
   -A clean room frock - In general, a regular cloth lab coat is not adequate as they can produce lint. Disposable clean room frocks are usually available in the entry way or from the lab coordinator.
   -Second pair of shoe covers - Probably the largest source of contamination in the clean room comes from shoes that have walked across campus and picked up mud and dirt before entering. If your shoes are wet and especially if you have aggressive soled shoes that hold mud, we ask that you bring a second pair of clean shoes and change into them before entering MH425 (the main lab). When you entered MH425, you should already have put on one pair of shoe covers. Now put a second pair of covers from the bin inside the clean room entrance area over the first pair of booties. The first pair of booties have already been in the main lab where they picked up dirt. Wearing those directly into the clean room would track in that dirt. Our entry way is a type of load lock, where we cover dirt and dust before entering the clean room. Remove the covers and leave them in the entry room when you leave.
   -Latex gloves - available in the entry room. These can be disposed of in the main lab when you leave the room. If they have chemical contamination, they should be disposed of using proper chemical disposal procedures.
   -Hair bonnet - available from the lab coordinator.
   -Safety Glasses - If you are working with chemicals and/or the fume hood you must wear safety glasses. If you are using the resist spinner you must wear safety glasses and make sure everyone else in the room is wearing them as well since the wafers spin at high speed and chards from broken wafers can become projectiles.
4. Entering and leaving the clean room - Once you are "gowned up" you can enter the room, be sure to walk across the sticky floor mat to take any residual dirt and dust off your booties. Do not bring any new equipment, or items (other than normal samples) into the room without permission. In particular, dusty items like cardboard or chairs with fabric seats should not be brought into the room. YOUR COMMON SENSE IN MINIMIZING DUST CAN HELP ALOT HERE. When you leave the clean room, remove your clean room clothing and leave it in the entry way. If you notice damaged or dirty booties please discard them. Contaminated gowns should be set aside for proper disposal.
5. Fume Hoods and Chemical and Gas Usage - The hood is a special nonmetalic clean room hood. Do not attempt to clean the hood glass with solvents. Acetone attacks the sash. You can see the results of a prior attempt to do this on the hood. After you use the hood, its important to clean up completely, dispose of your chemicals properly, turn off equipment in the hood, and leave it so the next person can have easy access. You may use the hood for routine chemicals associated with photolithography (photoresists, solvents, dilute acids and bases etc.). No chemicals of any kind may be used outside of a hood. If you need to leave a chemical setup in a fume hood while you are not present in the lab, post a note on the hood to indicate you are using it. If you want to leave the set up in the hood for more than one day, then you must obtain permission in advance from the lab coordinator, and each chemical in the hood must be labeled in case the coordinator needs to make room for another user. In general, long term or permanent setups which keep others from using a hood will not be approved.
6. Chemicals- In general, you should not bring any new chemicals, other than routine photolithography chemicals, into the room. Ask if you want to. Chemicals need to be labeled, have your name, and be dated. Any chemicals which cannot be identified are VERY expensive to dispose. Mixed up chemicals or chemicals which are not in an original container (from the manufacturer) will be disposed of if left in the lab unused for long periods of time. Chemicals must be stored in proper locations (e.g. acids in ventilated cabinets under the hood), and taking into account compatibility issues (e.g. acids and solvents cannot be stored together). If you are in the least bit unsure, ask before storing. Each user must properly dispose of used chemicals in campus approved containers labeled with campus approved labels and arrange for pickup of the used chemicals. NEVER PUT CHEMICALS DOWN THE SINK.
7. Equipment access and use- In general, access to the lab includes training on and access to equipment. If a piece of equipment does not appear to operating properly, let the lab coordinator know immediately. The equipment is expensive, and its important we all work together to keep it functional. Failure to report a problem prolongs the time the tool will not be operational and could lead to additional damage to a tool by the next user. Also, if you are uncertain about how to utilize a piece of equipment, contact the coordinator or another user before proceeding.

This page last updated January 9, 2004