Hazardous Materials

This section provides detailed safety information on various materials used in the NCSU Nanofabrication Facility.  Please click on the links given on the left menu to access different material types.

Compressed Gases (NNF Staff Only)

Gas Procurement

All hazardous and flammable gases must be maintained in a designated, ventilated cabinet in a gas storage room. Gases for a system may be ordered after completion of a PHR of the system and approval of the PHR committee. If at all practicable, cylinders will be sized to provide a three month gas supply. In instances when a new gas is introduced to an existing process, temporary approval for use must be received from the chairperson or designee of CSAC. The temporary approval will undergo a routine review within thirty days.

Hazardous Gas Monitoring Requirement

All the requirements specified in the NC State Gas Monitoring Program must be met (see EHS home page).

The Principal Investigator of the equipment/process/experiment requiring gas monitoring shall ensure the following issues are addressed:

• Gas which requires monitoring, is specified in the NC State Gas Monitoring Program and shall meet all applicable requirements.
• Procurement of the gas monitor shall be approved by EHS.
• Emergency Response Plan/Procedures shall be reviewed and documented with the EHS, when required.

Compressed Gas Cylinder Safety

Arrangements must be made with authorized staff personnel before handling any compressed gas cylinders (transport to/from cleanroom, installation and removal of cylinders from gas cabinets). Only trained personnel will handle hazardous gases, unless previous arrangements have been made by the facility manager and /or students’ advisor. Cylinder changes of hazardous gases will take place only under the direct supervision of the facility manager or designee.

General

Compressed gases represent a special hazard. Each compressed gas cylinder contains a very large amount of energy. This energy, if released improperly, can result in a serious injury. In addition, gas hazards include flammability, toxicity, or corrosiveness. Refer to Material Safety Data Sheets for specific hazards. Hazardous gases must be received at the loading dock only. Hazardous gases must be leak checked, according to the leak check procedure, prior to going into the facility. Contact EHS immediately if cylinder is damaged or leaky.

A phone is located at the loading dock for shippers to notify you of there arrival. Cylinders may be placed in Room 131B for temporary storage. DO NOT LEAVE CYLINDERS UNNATTENDED AT THE LOADING DOCK.

Precautions

The following is a list of precautions that should be followed in order to minimize hazards associated with any compressed gas: All gas cylinders, full or empty, shall be handled in the same manner.

1. Do not transport gas cylinders without valve protection cap in place unless the cap is properly mounted for use on a service cart.
2. Do not roll cylinders or use for support.
3. Close valves tightly after use.
4. Do not place cylinders near furnaces or any source of heat. The cylinder temperature should not exceed 125°F.
5. Appropriately secure cylinders with safety strap, even when not in use, so that they can’t be knocked over.
6. Do not drop cylinders or handle them roughly.
7. Do not expose gas cylinders to continuous dampness, salt, corrosive chemicals or fumes.
8. Do not attempt to repair or alter cylinders or valves. If a cylinder is damaged or leaking, inform staff personnel, call EHS.
9. Never completely empty cylinders. Leave at least 5 pounds of pressure in the cylinder.
10. Preserve and comply with all markings and signs applying to compressed gas equipment and system.
11. No smoking is permitted while compressed gases are being used or handled.
12. Never have oils come in contact with compressed oxygen.
13. Always use non-sparking tools on compressed gas cylinders.
14. All hydrides must be ordered with DISS (Diameter Index Safety System) fitting and restrictive flow orifice (RFO).
15. All hazardous gases will be ordered with restrictive flow orifice (RFO).
16. Hazardous gas cylinders must travel on freight elevator only.
17. Hazardous gas cylinders an only be transported down West corridor on first floor and through cleanroom on second floor. They are not allowed in general personnel corridors at any time.
18. Tag cylinders “used”. Do not write on cylinder.
19. Do not store cylinders in locations where heavy objects may fall on them.
20. Store empty cylinders separately from charged (full) cylinders.
21. Do not store cylinders close to building air intake systems.

Gas Receiving and Transportation

Each Principal Investigator shall designate one or more of their trained research staff for hazardous gas transportation. This staff will have primary responsibility for receiving, leak testing, inter-building transportation, exchange, and hookup of hazardous gas cylinders. The designated staff must be certified in the use of Self-contained Breathing Apparatus (SCBA) and trained in the use of the cabinet gas manifold.   Contact NNF Laboratory Manager when transportation of hazardous gas is going to occur in the clean room.   Any planned activity that can disrupt the normal operation of the NNF must be approved by the NNF Laboratory Manager or the Director.

Gas delivery must be carried out through the authorized gas transportation routes included in this manual. Moving a hazardous gas through other corridors is strictly prohibited.

The procedures for receiving new cylinders and returning empty cylinders will be identical. “Empty” cylinders are never entirely empty and must be handled with the same caution as full cylinders. Vendors will be required to schedule deliveries in advance. Upon arrival at the loading dock, the vendor’s driver will call the laboratory to announce the arrival of the gas cylinder(s). The designated gas transportation persons will bring a portable gas detector and observe the following protocols:

Transporting Non-Hazardous Gases at MRC

1. Secure cylinder in transportation cart.
2. Cylinder is loaded on freight elevator.
3. Cylinder can be transported down any corridor.
4. Once it is off the elevator, cylinder is transferred to cleanroom cart and wiped down.
5. It is now transported through the cleanroom to the gas room.
6. After the used cylinder has been removed from system, remove it from the facility in the same manner that the charged one was brought up.

Transporting Hazardous Gases at MRC

1. Two people must be involved with the movement of hazardous gases.
2. Cylinder must be leak checked, according to written protocols, in gas cabinet in room 131B, prior to being transported to cleanroom.
3. Cylinders going to cleanrooms on first floor must use the west wing corridor only.
4. Cylinder going to plaza level must use freight elevator and bring cylinder through 240 cleanroom space.
5. Cylinder is loaded on freight elevator by one person (who does not ride up with the cylinder) while the other person goes to the cleanroom to call the elevator. DO NOT RIDE THE ELEVATOR WITH A HAZARDOUS GAS CYLINDER.
6. Once it is off the elevator, cylinder is transferred to cleanroom cart and wiped down.
7. It is now transported through the cleanroom to the gas room.
8. After the used cylinder has been removed from system, remove it from the facility in the same manner that the charged one was brought up.
9. Leak check cylinder in gas cabinet in room 131B.
10. Schedule return of empty cylinder. Empty cylinders should not be kept in the facility or stored indefinitely.

Leaking cylinder:

If a cylinder is found to be leaking, do not remove it from the gas cabinet. Call 911 if a safety threatening situation develops for any personnel in the building and immediately notify the EHS and vendor representative so that a mutually agreeable solution can be reached for cylinder returns.

Cylinder Changing Procedure:

Hazardous gas cylinder replacement requires two qualified personnel. Only qualified personnel (i.e. as described previously) are allowed to transport, handle, install or change a hazardous gas cylinder.

New or replacement cylinders must be installed in a gas cabinet upon receipt and cylinders may not be stored in anticipation of installation at a later time.

SCBA must be worn when changing hazardous cylinders.

Cryogenic Fluids

General

Cryogenics such as liquid nitrogen and helium are used in cold traps for vacuum systems and process gases. The tools that use cryogenic fluids are the evaporators and the Leak Detector.

Hazards

Explosion, spillage, frostbite, and escape of asphyxiating gases are some of the more common hazards. Cryogenic fluids will damage permanently some polymer materials making them brittle and causing cracks. Water piping and hoses can be damaged as well.

Handling

Only authorized personnel will service equipment requiring cryogenic fluids. However, for any exposure or short period of contact with cryogenic fluids, flush area of exposure with large quantities of warm water. Seek medical attention. When pulling off liquid, heavy gloves and face shield should be worn.

DO NOT TRY TO STORE CRYOGENIC FLUIDS IN ANY CONTAINER OTHER THAN DEWAR VESSELS OR DEWAR BOTTLES. FAILING TO DO SO MAY CAUSE CATASTROPHIC FAILURE WITH CONTAINER AND SPILLAGE.

Chemical Safety

• Always check the label of a chemical before using it.
• Do not use any chemicals that do not have any labels on them. If you come across one, notify the NNF lab manager immediately.
• Make yourself aware of the safety concerns and proper handling before starting your work.
• Always read the information contained in the Materials Safety Data Sheet (MSDS) for the chemical(s) you will be using in the laboratory.

Chemical Types

Solvents

General: A solvent is any liquid used to dissolve another substance. In microelectronics, solvents are used in many processes, including degreasing, stripping, wafer production, and photolithography. Workers are exposed to solvents mainly by inhalation and skin contact. Each solvent has its own unique properties and health hazards, but some generalizations can be made:

• Most solvents are highly flammable.
• Solvents can cause acute damage to skin and breathing passages.
• Most solvents enter the blood stream after inhalation; however, some can be absorbed through the skin.
• Long term exposure to even low levels can cause a variety of organ damage. Liver, lungs, kidney and reproductive organs can be damaged from repeated low-dose exposure. In addition, infertility, damage to the unborn, and cancer (caused by exposure to benzene and chlorinated hydrocarbons) can result.
• The exact health effects of long term exposure and the interactions of solvents with other chemicals may not be known at this time. Some solvents thought to be safe (e.g., benzene) are now known to be carcinogens. Therefore, solvents should be treated as potentially harmful.
• Adequate ventilation, safe storage, and protective garments are among the safety measures that must be used.
• Protective attire should be worn when pouring or mixing all solvents and photolithographical chemicals:
  • Safety glasses/goggles
  • face shields
  • Chemical gloves
  • Chemical aprons
  • Closed-toe shoes
  • Long pants
• When photoresist coating wafers, chips, etc., the following can be worn:
  • Safety glasses
  • Chemical gloves or PVC gloves
  • Closed-toe shoes
  • Long pants

ALWAYS WORK IN VENTILATED HOOD, NEVER INHALE VAPORS, NEVER OBSTRUCT PERFORATED EXHAUST HOLES IN HOODS

Acids and Bases

Acids and bases (alkaline) are used in a variety of processes in the microelectronics industry. Acids are used to clean and etch wafers and to clean quartz ware. Bases are used in photolithographical processes and etchant solutions.

All acids can cause injury (burns) when splashed on the skin or in the eyes. Vapors or mists from a solution can not only injure the eyes, but also the mucous membranes and respiratory system. The extent of the injury depends on the strength and type of acid and length of exposure. Effects on the skin range from mild rashes to severe blisters and ulcers (breaking through the skin). Effects on breathing range from irritation of the breathing passages to chronic bronchitis to pulmonary edema (fluid in the lungs). Long term effects of exposure and interactions with other chemicals are largely unknown.

In the event of skin/eye contact, exposed area should be flooded with water under emergency shower or eyewash for minutes. If acid comes in contact with clothing, remove clothing while under shower. This list is not a replacement for Material Safety Data Sheets (MSDS). Before working with any chemicals which you are not familiar with, MSDS should be reviewed. Consult Material Safety Data Sheets (MSDS) which are located throughout the facility and in the office, for additional information on any chemicals used in the facility.

Bases can cause injury (burns) when splashed on skin or in eyes. Vapors or mists from the solution can not only injure the eyes, but also the mucous membranes and respiratory system. Due to the permeating nature of alkalis, severe eye injuries can still happen with even a dilute alkali solution. Effects on the eyes include cataracts and glaucoma. Effects on the skin range from mild rashes to severe blisters and ulcers. Alkali burns are usually more severe than acid burns. Effects on breathing range from irritation of the breathing passages to chronic bronchitis to pulmonary edema. In the event of any exposure to eyes, rinse with water 30 to 60 minutes. In the event of skin contact, exposed area should be flooded with water under emergency shower or eyewash for 15 minutes. If bases come in contact with clothing, remove clothing while under shower.

Protective attire will be worn when pouring, mixing or processing wafers with any acids and/or bases:

• Safety glasses/goggles
• face shields
• Chemical gloves
• Chemical aprons
• Closed-toe shoes
• Long pants

NOTE: When working in or around acid hoods, always wear chemical gloves. Beware of any objects or controls on the interior or exterior of the hood, as they are likely to have been handled by someone with acid on their gloves.

Oxidizing and Reducing Substances

General: Oxidation-Reduction (Redox) reactions can occur in any of the physical states (gas, solid, or liquid). The reactions tend to generate heat and are often explosive. In any reaction of this type, both agents must be present (oxidizer and a reducer).

Usually, one or the other agents creates a hazard when coming into contact with a normally innocuous substance.

Precautionary measures:

• In general, isolate substance from other potentially reactive compounds.
• Use adequate protective gear when working with such agents.
• If the substances involved are not water sensitive, safety showers, sprinkler systems, and flushing hoses should be made available.

Refer to Material Safety Data Sheets (MSDS) to determine incompatibilities.

Storage and Handling

Storage

• Never store acids and solvents in the same cabinet or hood. An explosion or fire could occur.
• Only store chemicals in properly designated cabinets or hoods. (If there is any doubt about the proper location, ask staff member.)
• All containers must be labeled with their contents and owners name. Otherwise, they will be set aside for disposal and their owner will be suspended from the facility.
• Only chemicals approved by the Facility Manager may be stored in the facility.
• There are 3 chemicals cabinets located in 240 E (chemical storage room).
• Cabinets are for acid, solvent and bases.
• Should have one case of chemicals upstairs and remaining chemicals are located in the NNF Chemical Storage Room on the first floor.

Handling

• Always know the hazards before handling any chemicals. Read the Material Data Safety Sheets.
• Always wear proper protective attire, even when carrying a bottle from the storage cabinet to a hood.
• Using nitrogen guns, leak check gloves for pinhole leaks. Never blow into protective chemical gloves to inflate.
• Always transport chemical bottles in a bottle carrier.
• Verify hood is available and all equipment needed is present prior to bringing chemicals to hood.
• Open chemical bottles only inside hood.
• Wipe acid bottle exterior after pouring. First, use wet lint-free towels and then dry towels. Rinse towels with DI water before disposing in plastic lined trash container (un-rinsed acid contaminated rags present a fire hazard).
• When working for extended periods of time with acids or solvent, rinse gloves periodically and dry with lint-free towels.
• Take great care to avoid touching anything with contaminated gloves or garments. Doing so can leave behind enough material to injure the next person.
• Always rinse gloves and hands with DI water after handling chemicals.
• Hazardous chemicals must be received at the loading dock and transported on freight elevator only. Hazardous chemicals are not allowed down main corridors.
• Excess quantities of chemicals are to be stored in the NNF Chemical Storage Room on the first floor.

Unwanted Material Disposal

Disposal of “empty” bottles:

• Acids – triple rinse interior of empty bottles and rinse exterior in proper acid drains before discarding. Leave caps off after rinse has been completed. These bottles may be placed in regular trash.
• Solvents – “Empty” solvent bottles must be vented in the solvent hood where bottle was emptied for at least 48 hours before discarding. Mark on bottles with time and date bottle is to be removed, and initial. Leave aerated bottle uncapped and discard in regular trash.

Disposal of acids and bases (excluding Hydrofluoric Acid and HF solutions):

• Use aspirator for siphoning acids in acid drains; never use industrial or water drains.
• Rinse acid tanks after aspirating and aspirate empty tanks three times with DI water.
• Clean area around acid tanks after emptying tanks or completing an operation. Use wet-lint free towels and then follow with dry lint-free towels.
• Rinse towels thoroughly with water before discarding in plastic bag lined trash can.

Disposal of Hydrofluoric Acid and HF solutions:

• The acid neutralization system is not designed to be used with HF.
• DO NOT USE INDUSTRIAL OR WATER DRAINS.
• Use rinsed out plastic chemical bottle for HF waste.
• Mark out old label and clearly mark contents of bottle, initial and date. Contact NNF Staff for Hazard label.
• HF etches glass. Do not use glass bottles!
• Acid waste pick-up is scheduled by Campus Hazardous Materials (ext. 5-6863).

Disposal of solvents:

• Aerated solvent bottles are used as waste containers for solvents.
• Waste bottle should be clearly marked for appropriate waste to be collected.
• Waste develop solution should be stored in waste container designated for waste developer.
• Solvent waste pick-up is scheduled by Campus Hazardous Materials (ext. 5-6863).

Chemical Spills

CAUTION: All chemical spills present an immediate safety hazard. Clean-up must be done immediately by NNF trained personnel. USERS ARE REQUIRED TO CONTACT NNF PERSONNEL  BEFORE ATTEMPTING ANY CLEAN UP. SAFETY SHOWER AND EYEWASH MUST BE USED FOR SPILLS ON CLOTHING AND FACE THAT CAUSE SKIN CONTACT WITH THE CHEMICAL.

Chemical Spill on Floor (over one liter):

During the normal operational hours (8 – 8PM, Monday – Friday):

• Attend to personnel who may have been exposed and help him/her reach the safety showers in the facility
• Notify the staff member in the facility.
• Evacuate the facility
• Do not re-enter facility until cleaared by authorized staff personnel and Emergency Response Commander.

Outside the normal operational hours:

• Attend to personnel who may have been exposed and help him/her reach the safety showers in the facility
• Shut off re-circulation fans using knife handle breaker switch.
• Evacuate facility.
• Call 911 and tell them you are calling from the NC State campus and that you require emergency assistance from Environmental Health & Safety, unless you require outside assistance such as medical services.
• Do not re-enter facility until cleared by authorized staff personnel and/Emergency Response Commander.

Solvents:

• Eliminate any source of ignition or sparks (such as hot plate).
• Use adequate amounts of lint-free towels to wipe up spilled solvents.
• Discard towels in plastic bag. Tie bag and label for disposal.

Acids (with no HF):

• Aspirate from work surface.
• Spray with DI water.
• Aspirate the DI water.
• Repeat preceding two steps.
• Dry area with lint-free towels.
• Rinse and dispose of towels in plastic lined trash container.

Acids (with HF):

• Spray with Team Low Na Acid appropriate neutralizer until there is a color change.  Start from outer edge and work inward.
• Aspirate from work surface.
• Spray with DI water.
• Aspirate the DI water.
• Repeat preceding two steps.
• Dry area with lint-free towels.
• Rinse and dispose of towels in plastic lined trash container.
• DO NOT STORE HF CONTAMINATED TOWELS IN REGULAR TRASH CONTAINERS.

Chemical Hood Operation

Acid and solvent hoods are considered process equipment or tools. The facility protocol and general rules must be followed for any chemical hood operations. Each hood is approved for specific processes. Do not transfer processes from hood to hood. Contact NNF Laboratory Manager if you noticed any safety violation regarding hood operations or processes being performed that are not approved for a specific hood.

1. Proper protective attire must be worn (see section Chemical Safety).
2. Only specific approved chemicals may be used for approved operations conducted in a particular hood. If you are using an approved chemical process that requires an approved secondary container it must be properly labeled with the Chemicals, User Name, Contact Information, and Time of Use. If materials are found without the proper labeling they will be disposed of.
3. Never touch the interior or exterior of chemical hoods with bare hands due to the possibility of chemical residuals.
4. Do not touch anything outside of chemical hoods with chemical gloves. Hood controls may be touched after rinsing and drying gloves.
5. Never submerge gloves in acids or solvents (pinholes are sometimes present). Gloves can be checked by using nitrogen guns to inflate glove then inspect for holes.
6. Blower should always be left on. Hood certification is valid only with blower on.
7. Hood sash should not be used above 11″ for optimum hood performance.
8. Light should be on while hood is in use.
9. DO NOT USE SOLVENTS IN ACID HOODS OR ACIDS IN SOLVENT HOODS. Explosion might occur. Exception: Ethylene Glycol or Triton X-100 (detergent).
10. Lights should be off when hood is not in use.
11. Ensure DI water, acid siphon, and heated baths are off when work is complete.
12. Carefully remove protective clothing and put in appropriate place.

NOTE: Be familiar with the hazards, toxicity, and flammability of all gases and chemicals used in this cleanroom. Most of these gases and chemicals can present a life-threatening hazard.

Chemical Contact to Skin

• In the case of a chemical contact to the skin,
  • Flush with water for at least 15 minutes
  • Remove contaminated clothing while water rinsing
  • Alert lab personnel
  • Get medical attention taking the MSDS of material you are exposed to.
• Hydrofluoric acid and mixtures containing HF may not cause an immediate burn sensation; however, they can result in severe burns.
  • Calcium Gluconate ointment can be applied after thorough water rinse, prior to seeking medical attention.
  • The gel is located in chemical hoods.

Chemical Contact to Eyes

• Flush with water for at least 15 minutes for acids/solvents.
  • Alkalis should be flushed 30-60 minutes.
• While flushing, lift upper and lower eyelids
• Get medical attention as quick as possible, regardless of how your eyes feel.