Rules of Operation for the
Lutz Microfabrication Cleanroom

GENERAL RULES AND RESTRICTIONS

1. The only individual qualified to work in the cleanroom are those who have satisfied all conditions in the document entitled Who is Allowed to Work in the Cleanroom

2. NO makeup shall be worn inside the cleanroom.

3. Food and drinks are prohibited in the cleanroom.

4. Smoking is not allowed 30 minutes before entering the cleanroom.

5. Chewing gum is not allowed in the cleanroom.

6. Avoid wearing contacts. 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 contact 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 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.

7. 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 step in a mud puddle on the way to the cleanroom, you're out of luck.

8. Only use pens and cleanroom paper. Lead pencils are not allowed in the cleanroom.

9. Bunny suits, booties, mustache/beard nets, and gloves must be worn at ALL times in the cleanroom.

10. Your name MUST appear on the QUALIFIED USER LIST to operate ANY piece of equipment in the CLEANROOM. Exceptions are the following only:

    Non-programmable hotplates in the fume hoods.

    Nitrogen guns and DI water.

11. All cleanroom equipment usage must be entered in the respective log manual along with any unusual occurances.

12. Chemical and gas usage must be recorded in the log sheets.

13. Nonessential items of equipment (tools, books, etc.) will not be allowed to accumulate and will be removed from the lab at the discretion of the Microfabrication Lab Manager.

14. Gloves must be worn at all times inside the cleanroom.

15. Try not to sneeze or cough in the cleanroom. Don't breathe directly on a clean surface or wafer. Singing, whistling, and chewing gum also produce severe contamination. Do not let your skin touch any surface in the cleanroom. In particular, don't touch your face and then a lab surface. Your skin will leave behind oils. If you believe something has been contaminated, contact the lab manager or lab technician.

16. Once inside the cleanroom, there are a few precautions you can take to maintain cleanroom integrity. Do not enter the HVAC chase area. Be aware if you tear any part of your bunny suit or booties. Move slowly and carefully to minimize air turbulence. Don't slam any of the doors; this also creates turbulence and shakes the partitions, resulting in additional contamination.

17. Always clean up your work area before you leave. Thoroughly rinse the beakers you used with DI water and then store upside-down in their appropriate locations.

SAFETY RULES AND RESTRICTIONS

The chemicals used in the Microfabrication Facility are extremely hazardous. Table 1 below lists some of the more common chemicals used in the lab and their concentrations. 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 minimized.

1. DO NOT use a chemical in the cleanroom without first reading its MSDS.

2. Know which chemicals and containers are compatible. Some chemicals, such as TCE, cannot be used with plastic beakers. Some chemicals, such as HF, cannot be used with glass beakers.

3. Always work with chemicals under the fume hood. Heavy-duty rubber gloves, a chemical apron, and a face mask must be worn when handling hazardous chemicals in the cleanroom. Table 2 below contains a list of some of the corrosive liquids used in the lab.

   Table 2: Some Corrosives Used in the Microfabrication Facility

   Chemical Type	Chemical
   Corrosives
   	Ammonium Fluoride
   	Ammonium Hydroxide
   	Buffered Oxide Etch; [BOE]
   	Hydrochloric Acid
   	Aluminum Etch 80-15-3-2
   	Hydrofluoric Acid
   	Phosphoric Acid
   	Potassium Hydroxide
   	Resist Developer
   	Sulfuric Acid

4. Use the DEDICATED beakers only with the chemicals and/or process labeled on the beaker. Do not cross-contaminate beakers. Do not remove beakers from the cleanroom.

5. When mixing chemicals, use only one bottle at a time. Do not open a new bottle unless an existing bottle is completely empty. 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.

6. Don't pour chemicals back into the storage bottle. If you pour out too much, dispose of it appropriately.

7. Put the cap back on each chemical bottle securely. Rinse the outside of the bottle before you return it to storage.

8. Exercise extreme caution at all times! Because most chemicals used in the lab look like water, always assume any liquid is dangerous.

9. Do not leave your chemicals unattended. If the chemicals will be in use for several hours, arrange with the lab manager or lab technician 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 next to the chemicals.

10. 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 a teflon or plastic beaker on a hot plate. Always monitor the temperature of the chemicals on a hot plate with a teflon coated thermometer. Table 3 lists some of the flammable chemicals encountered in the cleanroom.

    Table 3: Some Flammable Chemicals Used in the Microfabrication Facility

    Chemical Type	Chemical
    Flammables
    	Acetone
    	Chlorobenzene
    	Methanol
    	Isopropanol
    	Resist Primer
    	Xylene

11. Rinse the heavy chemical gloves with DI water before you take them off.

12. Always clean up your work area before you leave. Thoroughly rinse beakers you used with DI water and then store upside-down in their appropriate locations.

13. Two fire extinguishers are located in the Cleanroom. One is located outside the pholithography room and is a CO₂ type. The other is located in the furnace chase area and it is a powder type. The eye wash station and shower are located near the cleanroom entrance.

14. Gas masks are located in the cabinet to the right of the fume hoods in the class 1000 area.

15. Tell your supervisor about any unsafe situation. Use your judgment. For example, if a beaker of chemicals is sitting around without a label, report it.

16. If you are not sure something is safe, ask your supervisor. Use common sense. There are no unexpected dangers in the microfabrication lab, but do not touch anything unless you are sure you understand it.

17. Wear safety glasses when using the spinner. Safety glasses are available in a box to the right of the spinner. The spinner sometimes breaks silicon wafers. When this happens (about once every thousand wafers), silicon shards may be ejected. Silicon chips are about as dangerous as broken glass. Wear safety glasses when using the spinner to protect your eyes from flying chips. It is a good habit to always wear safety glasses in the microfabrication labs, taking them off only to use a microscope. This is a rule for everyone in a room when someone in that room is doing spin, develop, etch, or strip. Aprons are available to protect your clothing. A drop of photoresist may splash onto your clothing and make a permanent spot. The spinner is well ventilated; if you smell the solvent in the room, discontinue work and notify the lab superior. Open your resist vial close to the spinner chuck; opening far away from the chuck ventilation may cause other students to smell the solvent. These solvents are known to cause birth defects when inhaled by pregnant women.

18. Hydrofluoric acid (HF) is more dangerous than it seems. Because HF does not hurt when it makes contact with skin, people get careless. HF hurts badly when it makes contact with eyes, lips, fingernails, etc. The pain may not start for a few hours, but it may last for days. For HF burns, get medical help immediately.

19. Wash your hands when you leave the microfabrication lab.

20. Policies for Gases:
    1. New gas cylinders should be labeled with the date of arrival.
    2. Empty gas cylinders should be labeled with date it was noted empty.
    3. Empty gas cylinders should be stored in gas storage cabinets

21. Policy for Chemical Storage:
    1. Chemicals are stored based upon their contents and color code. Only store chemicals in their appropriately labeled cabinets and locations.

22. Policies for Acid and Bases:
    1. When handling acids or bases, gloves, apron, face shield, and lab coat must be worn.
    2. All acid and base work must be done in an exhausted fumehood.
    3. Acids are stored in the cabinet labeled "ACIDS".
    4. Bases are stored in the cabinet labeled "BASES".
    5. Never work with acid and bases side by side because violent reactions can occur.

       Acids	Bases
       Acetic Acid	Ammonium Hydroxide
       Hydrochloric Acid	Potassium Hydroxide
       Hydrofluoric Acid	Sodium Hydroxide
       Nitric Acid	Pos. Photoresist Developer
       Phosphoric Acid
       Sulfuric Acid

    6. Disposal of acids of bases through the drain can occur only after a pH level between 6 and 8 is achieved through neutralization.
    7. Storage of waste acids will be done by storing the acids in clearly labeled waste containers for that particular acid. Do not mix the acids together. Waste acids should be stored in separate containers in the acid cabinet.
    8. Neutralization of the acids is done by taking approximately equal parts of Sodium Hydroxide solution placed in an open polypropylene container and slowly adding an equal part of acid until a pH between 5 and 8 is reached. Always pour the acid into the Sodium Hydroxide solution.
    9. Storage of waste bases will be done by storing the bases in a clearly labeled waste container. Ammonium Hydroxide will be stored in a clearly labeled waste container. Potassium Hydroxide, Sodium Hydroxide, and positive photoresist developer will be stored together in a clearly labeled waste container.
    10. Neutralization of the bases is done by adding Hydrochloric Acid to the base solution in an open polypropylene container in an exhausted fume hood until a pH between 6 and 8 is reached. Always pour the acid into the base.
    11. Storage of the waste acids will be in the acid cabinets and storage of the waste bases will be in the base cabinet.
    12. If any acids or bases are purchased by individual faculty or students, they must take the responsibility for the neutralization by purchasing the neutralization chemicals and mixing of the chemicals to achieve a pH between 6 and 8 before disposal down the drain with large quantities of running water.
    13. Small quantities of concentrated acids or bases (less than 75ml) can be poured down the drain as long as it is diluted with large amounts of tap water (not DI water).

23. Policies for Solvents:
    1. All chlorinated solvents must be stored in a clearly labeled waste solvent container for proper disposal.
    2. Trichloroethylene (TCE) and Trichloroethane (TCA) should be kept in a separate solvent waste container from Acetone, Methanol, and Propanol. Acetone, Methanol, and Propanol can be disposed of through incineration while TCE and TCA cannot because of carcinogens.
    3. On all solvent waste containers will be a label. On this label will be three columns that need to be filled out when a waste solvent is poured into that bottle. Column one is the CHEMICAL NAME, column two is the CONCENTRATION (%), and column three is the QUANTITY. The chemical name is the proper chemical name not the manufacturer's name. An example is Microposit Remover 1165 is the manufacturers name, the proper chemical name is N- methyl 2-pyrrolidone. Most solvent containers have the proper chemical names listed on them.
    4. Keep all flames away from the solvents because most solvent are highly flammable.

24. Policies for Solids:
    Solids must be stored in an appropriate container and clearly labeled for disposal through the safety department.

25. Policies for Mercury:
    Mercury can be picked up with a mercury spill kit, stored in a properly labeled container and disposed of through the safety department.