Introduction to the Facility
The Clean Room
Room 1224 Kemper Hall is a Class 100 clean room. 1254 Kemper Hall is Class 10,000. "Class 100" means that there are no more than 100 dirt particles per cubic meter of air. This is over a thousand times less than a typical office. Such cleanliness is important when fabricating very small devices. The air that enters the clean room passes through very high efficiency filters (HEPA filters) and flows from the clean room outwards pushing any dust out too.
Undergraduates gain access to the lab by taking the introductory EEC 146A & EEC 146B courses.
How to Enter the Clean Room
Do not smoke, eat or drink in the lab. Therefore, leave food and drink outside in a locker. Dispose of any chewing gum. Store your books, brief case, or anything else that you brought with you in a locker outside the lab. Do not bring a bicycle into the lab! If you are an advanced user, check out the additional entry information .
Before You Enter the Gowning Area
Check your clothing. Everyone must wear full-length pants when using the lab. You may put on a pair of pants over shorts. Avoid gowning over bare legs. Do not enter wearing sandals or open-toed shoes. Wear shoes made of leather that completely cover the foot. Do not wear muddy shoes. If you stepped in the mud on the way to the lab, you're out of luck.
Avoid wearing contact lenses. Contacts can absorb vapors or trap chemicals in the space between the lens and the eye. In an emergency eye muscles may spasm preventing removal of the lens. Contacts may thus interfere with flushing the eye with water and allow the eyes long and intimate contact with toxic chemicals. If you take your contacts off before you enter, don't bring them into the lab and store them near volatile chemicals. Leave them in a safe place outside of the lab.
Do not wear makeup into the lab.
Scuff your shoe soles on the entry mat in front of 1224 several times.
As you enter, take four to five baby steps on the tacky mats. This will help remove some of the dust from the soles of your shoes. Tacky mats will not remove mud from shoes.
Gowning
The greatest sources of clean room particulates are users. You will be the dirtiest object there! Thus, before going any further, you must put on clean room clothing. These garments help maintain the cleanliness of the lab. You must always wear them inside the lab, and never wear them outside the lab.
As you saw in the video, gown up from head to foot and de-gown from foot to head. Unlike the video, there is no obvious demarcation between the "cleaner" part of the entry area and the dressing area. Thus, imagine that the west end of the dressing benches forms a "clean line." Don't step beyond that line in your street shoes.
- First get your hood. You must
reserve your hood by placing a small label on your hanger. Get
a label from the TA. Do not write your name in pen on
your hood. The ink will leak particles into the cleanroom
atmosphere. No one else should wear your hood. Place it over your
head and snap the snaps. Do not be confused by the two inside snaps
that secure a face mask. Make sure you put the hood on outside out.
See that the hood covers your hair and ears. Tuck hair longer than
the hood's collar into the hood. If you have a beard or
mustache, use a hood that covers the mouth.
- Second, take an appropriate sized gown (XSmall-XXL). Look in
the cabinets for a gown if necessary. If a gown off the rack is
obviously dirty, place it in the laundry hamper. If it is damaged,
turn it in to the lab manger. Grab the two sleeves with one hand,
unzip the zipper and grip the end of the zipper with your other
hand. Try not to drag the legs on the ground. Step into the gown.
Place the gown's collar over the hood. Snap the collar, cuffs, and
ankles. You must fasten the snaps at the neck and wrists.
- Now, get appropriately sized boots from the rack. Turn down the
cuffs of the boots about three-four inches. This will prevent your
shoes from contaminating the outside of the
boots. Sit down on the west end of the changing bench to slip on
your boots. Pull up the cuffs and snap them. Fasten the buckles.
- Now, take out a pair of PVC gloves from the package at the west
end of the gowning room. These gloves keep the oils
on your hands from getting on the equipment. Note that the gloves
are packaged with all the wrists at one end. This makes it easier to
put them on without touching the fingers or palms of the gloves.
If you accidentally take more than two gloves by the
wrists, put the extra back. However, if you touch the fingers or
palms, dispose of them. Glove your hands.
- The teaching lab 1224B, is on your right as you enter (top of the map). The research lab 1224A, is on your left (bottom). Step onto the tacky mat to remove any dust on your boot soles. Take a few baby steps and open the airlock door. When the door snaps shut behind you, you'll hear the second airlock door release. You're in.
Once inside there are a few things you can do to maintain clean room integrity. Do not enter the service chases. Watch for the door stops on the floor. You might stub your toe and tear open your boot. Move slowly and carefully to minimize air turbulence. Don't slam any of the doors. This also creates turbulence and shakes the partitions.
Try not to sneeze or cough. Don't breathe directly on a clean surface. Singing, whistling, and chewing gum also produce severe contamination. Do not let your skin touch any surface in the Lab. In particular, don't touch your face and then a lab surface. Your skin will leave behind oils. If you believe something has become contaminated, contact the TA.
Chemical Use
The chemicals used in the Northern California Nanotechnology Center are extremely hazardous. Table 1 below lists some of the more common chemicals used in the lab and their concentrations.
| Chemical Type | Chemical | Concentration |
|---|---|---|
| Acids and Oxidizers | Hydrofluoric Acid (HF) | 49% |
| Hydrochloric Acid | 36% | |
| Sulfuric Acid | 96% | |
| Phosphoric Acid | 86% | |
| Nitric Acid | 68% | |
| Acetic Acid | 95% | |
| Hydrogen Peroxide | 30% | |
| Bases | ||
| Ammonium Hydroxide | 25% | |
| Potassium Hydroxide | 45% | |
| Solvents | ||
| Trichloroethylene | 100% | |
| Acetone | 100% | |
| Methanol | 100% | |
| Chlorobenzene | 100% |
These concentrations, necessary for microfabrication, are much higher than those found in conventional undergraduate chemistry labs. Many of these chemicals can cause severe damage to human tissue. Therefore, you must be alert and cautious when using these chemicals to avoid all contact with them. When you follow the safety procedures below, your risk of injury will be small.
Know Your Chemicals
Before using any chemicals, become familiar with their properties. A Material Safety Data Sheet, also known as an MSDS, is available for every chemical used in the lab. The gowning section of the lab has the set of MSDSs. An MSDS lists all known properties of a chemical including safety precautions and emergency procedures. You must also know which chemicals and containers are compatible. Some chemicals can't be used with plastic beakers. Others, such as HF, can't be used with glass.
When using chemicals, use a wet bench in 1224 or a fume hood in 1246, wear a chemical apron, a face shield, and heavy chemical gloves. Table 2 below contains a list of corrosive liquids used in the lab.
| Chemical Type | Chemical |
|---|---|
| Corrosives | |
| Ammonium Fluoride | |
| Ammonium Hydroxide | |
| Buffered Oxide Etch; (BOE) | |
| Hydrochloric Acid | |
| Hydrofluoric Acid | |
| Phosphoric Acid | |
| Potassium Hydroxide | |
| Resist Developer | |
| Sulfuric Acid |
When mixing chemicals, use only one bottle at a time. Pour the chemical slowly. Do not let it gulp. Remember the Triple A Rule: "Always Add Acid to water," never the reverse. This prevents violent splashing. Do not mix organic solvents with inorganic chemicals. This can result in a violent reaction or explosion.
Don't pour chemicals back into the storage bottle. If you pour out too much, dispose of it appropriately.
Put the appropriate cap back on each chemical bottle securely. Rinse the outside of the bottle before you return it to storage. (The Hydrogen Peroxide bottle cap must have a hole in it.)
Exercise extreme caution at all times! Because most chemicals used in the lab look like water, always assume any liquid is dangerous.
Do not leave your chemicals unattended. If the chemicals will be in use for several hours, arrange with the TA to leave them. In addition, clearly mark the name of the chemicals, your name, where someone can contact you, and when you expect to return on a clean wipe. Leave this sign in your work station.
When using hot plates, check that your beaker is both suitable for hot plate use and smaller than the area of the plate. Never use teflon on a hot plate. Also, never place teflon in an oven or furnace. Always monitor the temperature of the chemicals on a hot plate with a teflon coated thermometer.
| Chemical Type | Chemical |
|---|---|
| Flammables | |
| Acetone | |
| Chlorobenzene | |
| Methanol | |
| Isopropanol | |
| Resist Primer | |
| Xylene |
If you are an advanced user, check out the additional information about chemical safety .
Clean Room Supplies and Practices
The lab uses an extremely pure water called de-ionized or DI water. Allow the DI water to run for about 20 seconds before using it. This removes stagnant water in the line.
Use the pyrex and teflon beakers with DI water and electronic grade chemicals. Never remove these "clean" beakers from the lab, or the wet benches or flume hoods that it is assigned to.
The lab provides clean wipes that are especially made for clean room applications. They are expensive like all clean room supplies. Do not waste them! Do no leave single wipes on work table or wet benches. The wipes will be sucked into the wet bench or up into the hepe filters.
Never touch silicon wafers by hand. Instead, buy a special pair of tweezers designed for handling wafers. These are available at the medical supplies desk in the ASUCD bookstore.
Cleanup
Always clean up your work area before you leave. Thoroughly rinse the beakers you used with DI water and then store them upside down on the wet bench.
Rinse the heavy chemical gloves with DI water before you take them off. If the gloves are still clean, lay them on the counter with the palms facing up so that someone can use them again. If they are dirty, throw them away.
If you are an advanced user, check out the additional cleanup information.
Emergencies
First Aid
If you spill a hazardous substance on yourself:
- Go directly to the nearest eyewash and shower. If you exposed your torso or legs, first get under the shower and start the water. Next remove any clothing splashed with the chemical. Shower for at least fifteen minutes. When using the eyewash, hold your eyes open with your hands and gently lift your eyelids away from your eyeballs. Remove contact lenses. This is why you should avoid wearing contact lenses. They get in the way of an emergency eyewash and increase the severity of chemical burns.
- See MSDS for specific first aid responses.
- For ingestion, see the product label or the MSDS. Call 911 immediately.
- For inhalation, leave the lab immediately. Call 911 immediately.
- For skin irritation, any
eye injury, or contact with extremely
toxic substances,
- go to the Cowell Student Health Center (752-2300), or
- call the occupational physician at Employee Health Services (752-2330) between 8:30 AM and 5:00 PM (if you are an employee of the University of any sort and have had a work related injury),
- or go to Sutter Davis Hospital after 8 P.M. on weekdays and 6 P.M. on weekends and holidays. This is especially important if the exposure was extensive, around the eyes, or involves HF.
- Take off any contaminated clothing and treat it as hazardous waste
- You must report any possible chemical exposure, no matter how small to your TA.
Fire Safety
- First remove any injured person from the vicinity of a fire.
- Next pull one of the eight pull alarms located in the outer corridor. Memorize the pull alarm location nearest to the lab bay in which you will do most of your work.
- Then dial 911.The normal response time of the Campus Fire Dept. to the Campus Core area is three (3) minutes.
- Do not try to extinguish a fire.
- Evacuate calmly through the designated exits and assemble in the designated area outside. If you cannot vacate the building, stay low on the floor to avoid toxic smoke. As you exit, don't prop open any lab door. Make sure your exit door closes. Some doors may remain open from air pressure, notably those to the gowning room and chemical storage. Closing them will help contain the fire.
Electric Shock
TAs will receive, as part of their orientation, safety information about electric shock. If someone receives a shock,
- first make sure the victim is no longer in contact with the electric current. If the person still has contact, assume they are not grounded. If possible, shut off the current safely and quickly. Otherwise, use appropriate non-conductive material to help you break the current. Use extreme caution! Do not become another victim.
- Dial 911 immediately.
- If the shocked person does not lose consciousness or show obvious burns or signs of medical distress, the person may still need a medical evaluation. Call the occupational physician at Employee Health Services, 752-2330. The duty nurse will help you decide whether to seek further medical advice or not. Do this even if the victim says: "I'm fine." Oftentimes a person may receive unseen burns or heart damage and not be immediately aware of it.
- If the victim complains about the shock, escort them to a medical facility. Don't send them alone. If the heart muscle suffered damage they may have trouble along the way.
- Tell the TA at the earliest opportunity about the incident.
How to Leave the Clean Room
De-gowning
Reverse the above procedure. Take off your boots first, then your gown, next your hood, and last of all your gloves. Do not hang your hood and boots inside your gown. This will contaminate both your hood and boots with your body and clothing particles that have adhered to the inside of the gown. Place in the laundry any obviously dirty garments. Place dirty tacky mats and your PVC gloves in the trash.
Exit
As you leave, take with you your pen, lab book, tweezers, wafer box, magnetic tape, etc. If you are the last to leave, turn out the lights. If you've used any chemicals, wash your hands completely after you have left the lab.
If you are an advanced user, check out the additional exit information.