2 Contamination Sources Clean Room ProtocolThe NanoLab operates as a class 100 cleanroom. Since the NanoLab is not a profit-making organization, overall yield may not be an issue. Nevertheless, defects can delay completion of projects leading to missed deadlines for submissions. All labmembers have an interest in helping maintain the standard of cleanliness required for success.Contamination SourcesThe human body is the main source of contamination in a clean room. Humans are constantly shedding hair and dandruff, often spray saliva when talking and have a mixture of sweat and oils on their skin. Hair, dandruff and skin oils can lead to defects in masks. Sodium and potassium in body fluids are semiconductor poisons, which in small concentrations can drastically alter the conductivity of doped silicon. Minute traces of gold, which may rub off jewelry even in casual handling, can also poison semiconductors.Other sources of clean room contamination are ordinary paper, cardboard, pencils, dirt off the floor and dust in the air.
3 Control MeasuresThe NanoLab provides caps, coveralls and boot covers to labmembers. We encourage labmembers to change regularly, since once cover gear tears it generates particles.The NanoLab provides nitrile gloves (blue colored) to lab members. These gloves are available in bins located by the door to the lab. You must wear them at all times in the lab for the protection of lab surfaces from contamination of oils and salts on your hands. Keep your gloves clean; do not touch your face with them. If you do, change your gloves. Also change your gloves after handling your cell phone (glove exchange station on each floor).The NanoLab also provides polyethylene gloves (opaque). These gloves are available in strategic locations throughout the NanoLab, in baskets. Use them to control contamination. Put on a fresh pair of these gloves over the surgical gloves each time you handle any contamination–sensitive equipment or materials. Example: The loading of an evaporation boat or e-beam crucible or when handling cassettes and handles at the wetsinks.Labmembers may check out notebooks made with special clean room paper. Store your notebook in a ziploc bag when you take it out of the NanoLab. Always write your name on the cover page of your notebook; if you misplace it, it can be returned. You may also use ballpoint pens, laptop computers and tablets inside the NanoLab. Cardboard and pencils, however, are not allowed.
4 Lab EtiquetteMutual consideration of fellow labmembers is essential to the efficient operation of the lab.It will also make life more pleasant for all involved. Please think about how your would like other members to deal with you when you are working in a space shared by so many.Leave your work area the way you would like to see it when you come in:No acid on sink decks or tops, no unlabeled beakers. Place a blue process ID slip even if you leave the NanoLab briefly.No Fed Ex boxes and other shipping containers cluttering up the work surfaces or the counter in the lobby.Report equipment problems promptly on MERCURY via FAULTS.No used gloves or Techni-cloths lying around- there is a trash receptacle in every room.Always clean the manual photoresist spinner.No empty bottles lying around. Rinse thoroughly at the bottlewash, scratch the label and dispose. Return carriers to the chemical elevator (dumbwaiter.)Please place empty chemical bottles to be rinsed *in* the chem elevator, not in front of it.No partially full chemical bottles on the floor. Return them to their designated bins underneath the sinks.No multiple open bottles of the same chemical. Use what’s available before getting more. If you suspect contamination, mark the bottle and report it to staff.Reminder: once opened, a bottle may not be returned to the designated chemical cabinet.Do not overflow waste bottles. They are handled by several others after you. Be considerate.Do not abandon failed experiments or broken equipment. They can be traced back to you and may lead to your suspension or expulsion from the NanoLab.
5 Lab Etiquette (cont’d) At the wetsinksNo acid left behind! Acid and water look alike, so be sure to use the techni-cloths provided in the holders in each room to wipe up and dry down the work surfaces.*Dilute the puddle or spill with DI water, using the sink deck hose first, then wipe it up.Empty chemical bottles left on the floor surrounding the sink area(s) poses a safety hazard. “If you empty a bottle, rinse it.” Bottles that have been emptied are to be taken into Rm. 582A to be rinsed and properly disposed; specifically by being given a thorough rinse in the bottlewash then the label X-ed out with a marking pen to indicate the bottle has been rinsed, then disposed into the giant blue bin for glass or plastic located near the sink.Check out your own pair of chemical-resistant gloves from the office as there is really no way for you to know what the other person had on their (nitrile-gloved) hands before putting on the pair of chemical-gloves that you may have found on a tabletop which may be contaminated with chemicals.
6 Lab Etiquette (cont’d) In the yellow photolithography Bay 382:Always clean the manual photoresist spinner after each use and re-line it with clean foil.Dispose of the foil afterwards in the vented PR trash can at the sink area.Photoresist drips on the countertop or floor should be promptly wiped up with a techni-cloth then disposed into the above can. Small amount of acetone from the squeeze bottle at the sink may be needed to thoroughly clean up all traces of photoresist from a surface.Photoresist dropper bottles that you are finished with are to be placed into the “PR Dropper Bottle” collection container which is at the rear of the msink3 deck in that bay.The organic waste bottles (for and photoresist + acetone waste) in the recessed area of msink3 should never be filled to overflowing - when the waste is at the shoulder level of the bottle it is time for a bottle swap. Follow the posted instructions at the sink.Glass slides, syringes and other small sharp objects are to be disposed in the “sharps” container; there is one in each working area.Broken beakers and glass dishes are to be disposed in the round yellow glass disposal bin located through the plastic curtains off 582A.Techni-cloths used for non-PR wiping and worn out gloves can be tossed in the general trash can in that bay.
7 Lab Etiquette (cont’d) Gowning up:Follow the correct sequence to gown up by first putting on the bouffant cap, followed by the bunny suit and then the white shoe covers over the blue booties (which you have already put on at the lab entrance.) This sequence is reversed when removing these attire to minimize particles from falling from your hair and skin onto these pieces.Wear the bouffant cap as it is meant to be worn: all hair needs to be covered and/or tucked in.If your bunny suit gets torn or ripped, get a replacement the next time you are in the lobby as particles from your closing and skin can find their way out, through the torn area of the bunny suit, into the lab environment and clean surfaces.If your white Tyvek shoe covers bottoms are encrusted with dirt, then it’s time for a change. The same goes for the blue shoe covers which are put on first.The bunny suits need to be zipped all the way up, not partially. If you are wearing a sweatshirt with a hoodie, keep the hood tucked inside the suit.
8 Lab Etiquette (cont’d) General hygiene, i.e lab manners:Everybody needs to sneeze at some point, so be sure to sneeze away from your wafers and lab equipment (use the classic elbow rule.)If you do happen to sneeze into your gloves, please change them at once.The techni-cloths provided in each room also serve as the lab Kleenex, so please toss used ones into the trash rather than leaving them scattered on work surfaces. The same goes for used foam ear plugs: if they are no longer in your ears, they belong in the trash.Chemical bottles that have been opened cannot be returned to the chemical storage cabinets located throught the plastic curtains off Rm. 582A; there are chemical storage bins for opened bottles throughout the NanoLab underneath each sink.