SNF General Cleanroom Manual
SNF General Cleanroom Manual
Table of Contents
1.1.4 Member Responsibilities:
1.2.1 Equipment Use Fees and the Soft Cap System:
1.2.2 Requests for Adjusting Equipment Use:
1.3.2 Lab Management System (LMS):
1.3.4 Storage for Personal Items:
1.3.4.3 Storage Containers in the Cleanroom
1.3.7 Red Phone Intercom/Pager:
The Process and Materials Committee (ProM)
1.4.3 Faculty Advisory Committee:
1.5.1 Respectful Workplace & Code of Conduct
2.2 For Successful Experiments...
2.3.1 Training and qualification
2.3.2 Enabling and disabling Tools
2.3.4 Equipment Status and Problems
3.1 Safety Roles & Responsibilities
3.1.3 Labmembers are responsible
3.2.5 Protection from Chemicals
3.2.8 Minimize clutter and clean up after yourself
3.3 Working Alone & the Buddy Rule
3.4 Special Health Considerations
3.4.3 Chemical and Latex Allergies:
3.5.5 Electromagnetic Radiation
3.6.1 Fire Alarms Appearance/Location:
3.6.2 Toxic Gas Alarms Appearance/Location:
3.6.3 Acid Waste Neutralization (AWN) Alarm Appearance/Location:
3.7 How to Respond in Evacuations
3.7.1 Building Evacuation/General Building Fire Alarm:
3.7.2 Lab-only Evacuation/Local Alarm:
3.7.3 Calling Lab-only Evacuation:
3.8 How to Respond: Specific Situations
4.1.2 Room 155/ExFab Mavericks:
4.1.3 Station Specific training:
4.2 Chemical Safety Information
4.4.1 General use chemical storage and handling:
4.4.2 Storage for personal chemicals approved by the PromCom:
4.5 Response for Chemical Exposure or Spill
4.5.1 Before working with any chemical,
4.5.2 For any suspected exposure to skin or eyes, immediately rinse the affected area:
4.6.1 The Acid Waste Neutralization (AWN) System
4.6.3 Solvent Waste Collection, liquid or solid
- Waste containing toxics and heavy metals
○ Hazardous In-Use material forms
5. Transporting Chemicals in the Lab:
6. Mixing and/or Heating Chemicals:
4.8 Personal Protective Equipment
3. Personal-use chemicals must be appropriately labeled
○ Sulfuric acid and "Piranha" clean.
3. Hydrofluoric Acid and Fluoride Containing Chemicals.
○ BOE's ("buffered oxide etchants")
○ Calcium gluconate is used treat exposure to HF
1. Pyrophoric (flammable) Gases
5.1 Acceptable Cleanroom Materials
The following materials are generally acceptable to bring into the cleanroom:
The following materials are not considered cleanroom-compatible:
Manual wafer transfer using tweezers:
"Flip” or “Roll” Transfer" of wafers:
5.5 Cleanroom Gowning Procedure
Before entering the gowning room
Rules and Guidelines for Personal Lab Behavior
Acceptable Materials in the Cleanroom
5.6 Transporting Corrosives in the Cleanroom (acids/bases)
5.7 Transporting Solvents/Resist/Developers in the Cleanroom
5.8 Bringing Chemicals into the Lab
SNF is open to anyone from any academic, government, private or industrial organization for any type of research and development activity allowed by the following: All must abide by the SNF Code of Conduct and non-Stanford researchers must also abide by terms of the Service Center Agreement Forms. Commercial activities (namely, production of devices for sale) are strictly prohibited; although broadly defined R&D, such as prototype development, are within the acceptable scope. You must become a labmember in order to make use of any of the lab resources.
SNF is a "sandbox", where members can work hands-on. However, if you have a project and are unsure whether you have the time or expertise to execute this yourself, we offer several options for fabrication services. We also invite you to discuss your projects and these options with one of our technical liaisons.
Stanford University policy prohibits SNF and its Staff from being party to secrecy or disclosure agreements having to do with work being performed in the lab. However, SNF also makes no claims to intellectual property developed independently by researchers using the lab. For more specific detail, please refer to the SNF Agreement Form and the Stanford University Administrative Guide regarding intellectual property.
If you are publishing or presenting papers of work you performed in any of our facilities, please make sure to help us recognize NSF's support in making nano@stanford possible with the following acknowledgement:
Work was performed in part in the nano@Stanford labs, which are supported by the National Science Foundation as part of the National Nanotechnology Coordinated Infrastructure under award ECCS-2026822.
In less formal settings, please simply list the Stanford Nanofabrication Facility with your other acknowledgements. We greatly appreciate your support.
Fees are charged for equipment use, stockroom or lab supplies, and staff time. There is no charge being in the lab.Some equipment (such as microscopes) are no-charge.
For satellite labs outside the Cleanroom (ExFab and MOCVD labs), equipment use is strictly on an hourly basis. The soft cap applies to Cleanroom equipment – note that some ExFab equipment (i.e., hourly rates) are physically located in the Cleanroom, but will appear under “ExFab” in the lab management system. Please refer to the Rate/Fees for Lab Use for current rates.
Charges for equipment use begin when a member “enables” a specific tool on the lab management system (LMS) and stops when it is “disabled.” Each member is responsible for equipment charges, even if you forget to disable. Requests to adjust charges for equipment use should be made to the staff person responsible for that equipment, within two days of the time used. Requests made after the month-end close may be subject to an administration fee of one hour of staff time. Please note that adjustment requests due to equipment performance are subject to SNF’s “best effort” policies, as described in Exhibit B of the SNF Service Center Agreement form.
Staff charges may be incurred for: equipment training, processing services, member-requested equipment services, or administrative fees. With the exception of equipment training charges (which are disclosed on the Equipment pages), members should acknowledge staff support charges before services are provided. Please also note that outside the lab, staffers are available to answer questions and offer advice without charge. However, projects that require major technical assistance may become subject to staff support charges.
Invoices are issued to non-Stanford organizations using SNF. Payment terms are net-30 days after the last day of the month billed. After 45 days, SNF reserved the right to require a deposit for continued access. Labmembers can monitor their own lab charges (less overhead) at any time on the lab management system (LMS). Staffers can also provide this information on request.
SNF is open 24-hours/day, seven days/week, with lab use subject to the “buddy rule" and the annual University Winter Close.
As of February 1st, 2024, SNF is using the lab management software NEMO. NEMO was developed by NIST. Each labmember has a personal NEMO account, which is linked to one or more billing accounts. This permits you to "enable" only the tools that you have been trained and qualified to use. "Enabling" activates a piece of equipment and starts incurring charges for use. As in any other networked environment, you may use only your own individual account and access privileges; do not share your account name and password with anyone.
On-site and remote computing resources that support fabrication are available for labmember use.
Be aware that use of NEMO and all other networked systems at SNF falls under the Stanford Computer and Network Usage Policy.
No hazardous chemicals or materials are allowed in these storage areas.
We have red storage lockers in the hallway outside of the cleanroom that can be rented on a monthly basis. These lockers are for long term storage for industrial and outside academic users who do not have any other option for storage space on campus. Students and SLAC labmembers are expected to use their offices, dorms, Group space, etc. No hazardous chemicals or materials are allowed!
We have blue storage lockers in the hallway outside of the cleanroom. These lockers are for day use - a safe space to store purses, laptops, phones, etc while inside the clean room. They are NOT for long term storage. You must supply your own lock (TSA size, a regular masterlock is too large). Please be aware that locks and belongings are subject to removal, if a locker remains continuously occupied. No hazardous chemicals or materials are allowed!
We offer storage bins within the cleanroom. They come in three different sizes, and are rented by the month. No hazardous chemicals or materials are allowed!
Pricing for these storage options can be found on our Fee Schedule, listed under Inventory Rates.
To inquire about availability of the lockers and storage bins, please reach out to snf-access@stanford.edu.
Labmembers may purchase for lab use, such as wafers, boxes, cleanroom notebooks, tweezers, etc. Cleanroom suits and blue coats are also available here. Make sure to notify staffers if supplies are running low. Please do not take items to stock another lab; if you need a large amount of supplies, talk with staff.
Several landline phones are located throughout the lab. To dial within Stanford, only the last five digits are required. For local calls off-campus, dial “9” before the seven-digit phone number. For life- and health-threatening emergencies, you must dial “9-911”.
Several red pager phones are located throughout the lab, including the gowning room entry in the Main Lab Corridor. These red phones connect to the PA system that transmits throughout the lab. To page someone, lift the receiver, speak clearly into the phone, and then hang the phone up.
Safety in the workplace is the utmost priority for SNF. The Safety Team at SNF is committed to maintaining and improving safety in the lab, and to ensure compliance with the policies of local regulatory agencies. To report a safety concern, notify a Staff member or send an email to: snf-safety@lists.stanford.edu
The ProM helps labmembers with new chemicals, materials and processes. The primary consideration of the ProM is safety. Next, is to consider issues which may affect the research of others. To learn more, or if you would like to submit a ProM request, consult the Materials section of the Labuser Guide.
This biweekly meeting brings together labmembers, from newbies to experienced consultants, with staff from both SNF and SNSF, to brainstorm ways to fabricate and characterize stuff. Everyone is welcome to pose questions to the collective wisdom of the fab and characterization community. Look for the labmembers mail for the next scheduled clinic.
The Faculty AdCom meets on a semiannual basis with the SNF and Faculty Directors to decide on the broader technology needs and strategic direction of the lab.
The Stanford Nanofabrication Facility is committed to providing an environment that is conducive to high-quality research, learning and productivity, based on mutual respect for every individual and the diversity in our community and beyond. We strive for the highest level of interpersonal and professional conduct. As such, we must exercise courtesy, civility, mutual trust and respectful communication. All of us in this community must act with awareness of how our individual behaviors shape our community as a whole.
Current labmembers may bring visitors to tour and observe lab operations. Visits must be approved by SNF staff and each visitor must fill out an "SNF Visitor Form" acknowledging responsibilities.
Video cameras are installed throughout the labs and in the receiving/stockroom areas of the building. These cameras serve multiple purposes: they enhance safety, they provide security for protected/hazardous areas of the building, and they may be used for remote training purposes. Video is recorded, but is not viewable or accessible by the public. SNF’s video policies are governed by the University's policies on video monitoring.
Never work alone in a lab with chemical and physical hazards. See the buddy rules in the Safety-for-all section of the lab manual.
Effective and conscientious communication is essential for the health and productivity of our research community.
2.1.1 Equipment status. Make sure to communicate the status of a piece of equipment using the lab management system (LMS).
2.1.2 Individuals. Specific fab or equipment questions can be addressed to the appropriate staff person. Any labmember can be contacted by their email.
2.1.3 User Groups. Problems, questions or comments can be addressed to the subset of labmembers who use a specific tool, by using the lab management system (LMS).
2.1.4 The Labmember Community. The entire labmember community (all registered labmembers and affiliates) can be addressed using the labmembers email. Be sure to keep communications at a professional level and concern only matters that are of interest to this broad group. Please do not use it for non-SNF-related communications. Email lists are managed through Stanford’s mailman system.
Please keep your communications respectful and relevant to the community you are addressing. Questions about specific process recipes might be best directed to the mail list for that equipment. Announcements for technical and professional seminars and workshops are entirely appropriate for the SNF Labmembers email list. "Free ice cream on the patio!" would be welcome on the Labmembers email list, but one can imagine some topics that would probably not. Make use of these mail lists with some consideration for the audience.
We highly recommend that you:
Make sure to document your work as much as possible. Any small detail may be the difference between a functional or a non-functional structure. Given the time normally invested in a fab run, a little extra time invested in documenting can save you (and any fellow researchers following in your footsteps) many weeks of work. These details may be as simple as an added acid dip, or as obscure as a slightly modified recipe step in a plasma etch process. For examples of the kind of information you might collect, refer to the process run sheets on this site.
As an educational and research enterprise, SNF can only provide best effort support for our researchers; we cannot warrant project success nor can we guarantee performance of equipment or protocols. Understanding that equipment and lab resources are shared by a broad range of researchers and researcher needs, we recommend a "defensive processing" approach, as described below. The lab community of staff and fellow labmembers can help you -- and indeed, are the best sources of know-how for being productive in the lab.
Most of what you need to know to process is not Google-able or in the Methods section of any paper. And it's more likely than not that someone knows how to do something you are trying to figure out. SNF's greatest asset is its community: students, faculty, external researchers, and staff.
Training is equipment-specific and is arranged by contacting the responsible staffer listed on the equipment pages. Technical Liaisons are available to discuss process flow and materials issues -- this is helpful in determining which pieces of equipment may be most appropriate for your needs. Information about process capabilities and materials compatibilities cab be found in the Labuser Guide. Equipment and staff availability may limit how quickly your training request can be accommodated. Also, the amount of time it takes to become trained on a piece of equipment varies widely as it depends on the complexity of the operation and your requirements. Staff will work with your technical and scheduling needs. Once you've demonstrated your knowledge and ability, you will be added to the "qualified users" list, which gives you privileges to enable, disable, and reserve this equipment.
Each piece of equipment in the lab is interlocked to the lab management system (LMS) NEMO . In order to use a tool, it must be "enabled". Only qualified users may enable and use a particular tool. In general, if use of a tool prevents others from accessing this capability, the user must keep the tool enabled for the duration of use, even if unattended. There are exceptions, indicated in specific equipment pages for these tools. When you are done using a tool, it must be "disabled." Make sure to check before leaving the lab for the day that your tools are disabled. If you forget to disable, this discourages others from using this system and will also continue to incur charges. And be a good lab citizen by reporting any problems you encounter, or shutting down equipment if it is not usable.
Labmembers can reserve equipment, subject to some restrictions. First, you must be qualified user. Second, there are limits on reservation horizon time, with default as one week in advance. Third, there may be limits on reservation length (one example would be two-hours maximum between 8 am-5 pm weekdays). Reservation rules for each tool can be access from the Policy tab on the lab management system. In addition, make sure to observe the following equipment reservation etiquette rules: - Don't over-reserve. Reserve just the amount of time you realistically need. - Release unused reservations on the lab management system as soon as you know you will not be able to use. This released the time so others may use. - Notify others of a reservation cancellation on high-demand tools. You can use the tool email list. - Do not reserve time for others. - 15 minute rule. If someone does not show up after 15 minutes, they lose their reservation. - Communicate, communicate, communicate. Problems happen. Someone may need more time or be late to their reservation. Make every attempt to communicate your needs and respect those of others; work out differences in a professional, courteous manner.
All lab and staff members must report process and equipment problems so that anyone can check the status of any equipment. Each tool can have one of the following equipment states: - Up: means the equipment is fully operational. - Problem: means the equipment is operational, but must be used with caution. Make sure to check the equipment messages for any special instructions; failure to do so could result in damage to your samples (or even equipment!) And if you observe a problem, however minor, report it; your fellow labmembers will appreciate it! - Shutdown: means the equipment is shut down and cannot be used. If you are using a tool and it experiences problems, you may be required to use the "Shutdown" function -- your training and the operating procedures will cover the circumstances and procedures for when shutdown is required.
2.3.5 Equipment repairs. Unless your training covers it, you should not attempt to repair equipment. Your help, however, in observing and noting the symptoms of any equipment problems is much appreciated.
Not all labmembers require access to all the SNF lab spaces. However, all labmembers must become familiar with the hazards in the building they will be working in regardless of whether there is any contact with any chemical or physical hazards. And some labs require additional training for hazards specific to those labs. The training requirement for each of the labs is summarized below. By default, the full building and cleanroom tours are scheduled for all new labmembers; make sure to inform snf-access@stanford.edu if you require the building tour only.
Lab Space | Required Safety orientation | Additional Requirements for Access |
Cleanroom | Bldg & Cleanroom tour |
|
ExFab | Bldg & Cleanroom tour |
|
Bldg tour | Experiment review with staff and Mavericks Policies | |
Bldg tour |
| |
Bldg & Cleanroom tour | Only MOCVD users may access |
Before entering any lab spaces, make sure to wear appropriate street clothing, which includes long pants (or equivalent) that cover legs, and closed-toe shoes that completely cover the feet. This table lists the dress code for entering these lab spaces. Note that additional PPE is required for certain specific operations, especially with chemical handling.
Click here for more detailed informantion.
Lab Space | Lab Dress |
Cleanroom | Safety glasses, gloves, hair net, shoe covers, bunnysuit. Cleanroom boots are recommended/required for some operations. |
ExFab | Safety glasses, gloves, hair net, shoe covers, polypropylene coat (cranberry or blue) (provides splash protection from non-hazardous fluids) |
Mavericks/Room 155 | Safety glasses, gloves, blue fabric (when handling chemicals) or polypropylene coat (cranberry or blue) (provides splash protection from non-hazardous fluids) |
Ocean/Room 151 | Safety glasses |
The MOCVD Lab | Safety glasses, gloves, hair net, shoe covers, blue fabric coat (non-flammable) (not poly) |
for preventing accidents, so must:
a) understand safety hazards and
b) observe safety precautions.
But no system is perfect. Everyone also has a role in responding in the case of an accident and in the post-incident analysis.
is to
a.) educate and inform labmembers of safety hazards and response procedures in the lab;
b.) provide the tools and resources for safe lab use; and
c.) continually improve safety by identifying, analyzing, and responding to safety concerns.
General lab safety hazards are communicated through this SNF Labuser guide and Stanford’s EH&S safety programs. Specific station-level safety hazards are communicated through training for individual tools. Safety resources provided by SNF include, but are not limited to:SDS information; operating procedures and training for each tool; personal protective equipment (PPE) and training in its use; documented procedures for actions to take in an emergency situation; knowledgeable personnel who are trained in safety and emergency procedures.
for behaving in a safe, conscientious, and professional manner in all lab activities. SNF provides information and tools; use this information to manage, not only your own safety, but the safety of your fellow labmembers and staffers. Be aware that anyone endangering themself or others will lose access to the lab. We all know that researchers need to try new things. So your responsibility is to work with staff to ensure that any new procedure/chemical/equipment is introduced and executed in a safe manner, through the ProM. You are also responsible for keeping the lab community safe by reporting any safety concerns. To report any potentially unsafe conditions or practices, or to offer suggestions for improvement, you can send a confidential email
These (and gum chewing) are NOT ALLOWED in labs. However, you should take frequent breaks and stay hydrated. Note that the only lab space where drinking is allowed is at the water dispenser in the Service Area near where you exit the Cleanroom. Do not bring food or drink into the Cleanroom.
In labs, take care to avoid collisions and injury to others. Avoid sudden or fast movements (no running). Prevent collisions by approaching blind corners slowly. Carefully approach and open all doors slowly. Remember that you and those around you may be handling or carrying valuable experiments that could be dropped and damaged.
In all labs, eye protection (see below) is required and shoes must fully enclose feet (no sandals, open toe, or sling-back shoes). Your clothes should be light and comfortable enough wear under a lab coat or cleanroom suit, as required. Legs must be covered in wet labs (i.e., no shorts or short dresses). Each of the labs will have specific lab dress requirements.
Safety glasses or goggles should be worn at all times in all labs; the only exception is when using a microscope or equipment with eye pieces. Eye protection must conform to ANSI standard (marked "Z87".) For labmembers requiring corrective lenses, impact-resistant prescription safety glasses with side shields may be purchased from most prescription glasses suppliers. Contact lenses are allowed under regulation safety glasses (but not allowed with full-face respirators or SCBA’s – applicable to staff only.) Side shields that can be used with regular prescription glasses are available in the Stockroom; please note that these may be used only with large framed, impact-resistant lenses and not recommended for long term use.
Operation of wet chemical benches and transportation of hazardous chemicals in the lab may require additional Personal Protective Equipment (PPE), which includes chemical apron, chemical-resistant gloves, full face shields, and boots, as described in the operating procedures for each station.
The background noise levels in labs are well within OSHA limits for 8 hours of continuous exposure. However, many staff and labmembers find it more comfortable to work using noise cancelling headphones or ear buds. Disposable foam ear plugs are provided for lab use. While hearing protection is highly encouraged, please make sure you are still able to hear alarms and other people in the lab (do not use headphones for entertainment.)
Broken glassware, broken wafers, razor blades/scalpels/XActo knives, syringe needles, etc. are sharp materials that can cause injuries, especially if they are contaminated. Do not dispose of sharps in the regular trash as this puts people, especially custodial staff at risk. Instead, dispose in dedicated Sharps containers located in the Service Area and in room 159 (the Wafersaw room), which will be picked up by EH&S and disposed of in its entirety.
Remove or store everything you brought into the lab. Label all personal belongings. Always be aware of your work area and be sensitive to what others are doing around you.
No one may work in the lab without a buddy at any time. The lab is open all hours, but there are times, such as a late night or on a holiday, when there may be no other people in the lab. If you expect to work when the lab may be empty, make sure to coordinate your work schedule in advance with a buddy. Working-alone rules are described below and detailed on Stanford's EH&S site.
An “in-person buddy”, who is physically present and within hearing distance, is required when performing higher-risk tasks. At SNF, pouring corrosive baths is a higher-risk task requiring an in-person buddy. Other operations may also require an in-person buddy, as described in operating procedures and training.
Except where specifically indicated, the buddy rule for lower-risk fab processing can adapted. A “semi in-person buddy” is another labmember who may not necessarily be in the same lab space, but is physically present on-site. A “live remote buddy” is someone who is continuously observing your activities remotely. An “asynchronous remote buddy” is someone who is not on-site.
Make sure your Buddy knows where you are working, how long you expect to be working, when to check in, and when you are leaving for the day. And if you are a designated buddy, make sure you communicate with your buddy partner. Do not leave your buddy partner without informing them.
While the physical and health risks in the labs are well within regulatory requirements, these regulations are designed around the general population. Certain individuals with health or physical concerns should review hazards presented and consult with their physician before working in labs. Here are examples of health conditions that may require additional consideration.
Equipment in the lab may serve as sources of high voltage, ionizing radiation, ultrasonic interference or electromagnetic interference, which may affect normal operation of a pacemaker. If you have such a device, you should consult your physician before working in the lab.
Labmembers who are expecting or contemplating pregnancy should be aware of potential reproductive health risks in the lab, such as volatile organic compounds (VOC’s). Concerned labmembers should discuss with their physicians and consult with their supervisors and SNF and University safety personnel as appropriate.
Certain chemical compounds may trigger allergies in sensitive individuals. One common sensitivity is to latex, found in the cleanroom gloves. Vinyl and nitrile cleanroom gloves are provided and may be used in place of latex. Other chemicals in the lab may also trigger allergies. Learn to recognize the signs of contact allergic reaction (skin sensitivity, hives, wheezing). Be watchful of your health and well-being.
Compressed gases pose both chemical and physical hazards. Some of the gases used at SNF are inert; others are toxic, corrosive, flammable, or explosive. The primary health risks posed by gases are the physical hazards (fire, explosion) and inhalation (toxics and corrosives.) Use of these gases is strictly determined by state and local regulations, and university policy. Engineering controls are used to minimize the possibility of release and exposure. Our toxic gas monitoring system is used to detect trace signals of a possible release and protect lab and building occupants by invoking evacuation. While these measures are protective, as a labmember, you must still be always aware of the types gases and the hazards posed in the equipment you use.
present exposure hazards because: a.) they have to be handled (transported, poured, and mixed) to be used; b.) each chemical poses different hazards and precautionary measures for use. The chemicals commonly used in the lab can cause severe burns, tissue, and organ damage, and can ignite and explode. The greatest health risks posed by liquid chemicals are physical (fire, explosion), direct contact with skin and eyes (tissue damage), and inhalation (pulmonary damage or long term chronic effects). Make every effort to understand the chemical processes you use and respect the chemicals you work with. Knowing the general rules for how to safely transport, pour, use, and dispose of these chemicals is the responsibility of every labmember' using wet labs.
are present wherever electricity is used. Although equipment is interlocked to prevent operator exposure, you must be aware of the electrical hazards for the tool you are using. Unless it is in your training, never open electrical enclosures or cabinets on equipment, even when the power is off. If you notice any electrical hazard (for example, an electrical "tingle" when you touch a piece of equipment) stop using the tool and immediately notify a staffer. Never put hands, fingers or conductive tools inside equipment. With the exception of personal electronics devices (laptops, phones), any electrical equipment brought into the lab must have prior ProM approval, to ensure that you can use the equipment in a safe manner.
is a potential risk in plasma etch, plasma deposition, and sputter tools, where highly energized species are generated. High power UV lamps are used in the aligner and stepper tools in photolithography; as they are mercury-based, they also pose a chemical risk (if a UV lamp should break or explode, do not attempt to clean up; instead, isolate the immediate area and call staff.)
may be generated by equipment using RF (primarily plasma etch and plasma deposition tools.) If you have a pacemaker, be aware that RF sources are present in the lab. All equipment is shielded to prevent exposure; report any damage to shielding on the equipment or cables.
Strobes are located in the lab and throughout (both inside and outside) the Allen/Annex buildings. The strobe is a small, rectangular, white light, usually with a red frame.
In alarm: the strobe flashes and a very loud, pulsing klaxon sounds and all alarms in the lab, Allen, and Annex buildings should go off. The toxic gases in the lab will shut off immediately and the Palo Alto Fire Department will be called.
Action: Stop what you are doing. Immediately leave the lab and the Allen/Annex buildings through the nearest exits. Go to the designated evacuation point.
Toxic gas beacons are located in the lab and throughout (both inside and outside) the Allen/Annex buildings. The beacon is a large, cylindrical, blue lamp.
In alarm: the beacon flashes and a very loud klaxon sounds continuously.
Action: Stop what you are doing. Immediately leave the lab through the nearest exit.
If the Fire Alarms are also activated, leave the Allen/Annex buildings through the nearest exits and go to the designated evacuation point.
The Acid Waste Neutralization (AWN) system beacons are located in each section of the lab, over wet benches and in the Main Lab corridor. The beacon is a yellow, rectangular light. Alarm conditions: the strobe flashes the AWN is no longer able to sufficiently neutralize the acid and base waste. The alarm is not audible. Always check the alarm before beginning processing on an acid/base wet bench.
Action: When active, do not use acid/base wet benches. In alarm, no solutions may be aspirated, drained, or poured down the drain of any acid/base wet bench. Solvent benches are not affected.
Allen/Annex Building Emergency Response Procedures and emergency contact information are posted throughout the lab and the building (look for the brightly colored signs near exit doors, fire alarms, fire extinguishers, and building phones.)
In an emergency, the priority is to move everyone safely away from hazards. When an emergency requires the evacuation of the building, the fire alarm system will sound. The fire alarm is automatically activated by smoke and fire detectors located throughout the building. Toxic gas detectors in the labs will also activate the general fire alarm. The fire alarm can be activated manually as well, by pulling the handle at any one of the pull stations located throughout the building. The Palo Alto Fire Department will respond to a general building fire alarm. All labmembers should familiarize themselves with the location of lab and building exits, the Evacuation Assembly Point, fire alarm pull stations, and fire extinguishers. When the fire alarm is activated, leave immediately. Do not take time to finish your tasks, remove your bunnysuit or collect belongings. Leave the lab and building through the nearest exit and go to the Evacuation Assembly Point (EAP #104). Provide assistance to others as necessary. Provide information that may be of assistance to Emergency Response personnel. Do not reenter the building, even if the alarms have silenced. Only after the Fire or Police Departments declare the scene safe will you be allowed to re-enter the building. While safely away from the building, wait for instructions. You may remove your bunnysuit. Keep it, so that when the OK is given to return to the building, you may check your suit into the laundry and check out a fresh set. Do not re-enter labs until staff have communicated that it is safe. Let staffers know if you have any work underway or in process, so they can prioritize tasks in bringing the labs back up.
Response for Building Evacuation/General Fire Alarm: - Leave the building immediately. Go to the Evacuation Assembly Point (EAP #104). - Do not re-enter the building until cleared to do so.
A lab-only evacuation may be activated by toxic gas detectors in lab support areas. In a lab-only evacuation, the blue, Toxic Gas Beacon is activated, but the general building fire alarm is not. When in the lab, you must leave immediately. Do not take time to finish your tasks in the lab. Do not take time to remove your bunnysuit or pick up your belongings. Leave the lab through the nearest exit and assemble in the office area outside the lab. While safely out of the labs, wait for instructions. You may remove your bunnysuit. Keep it, so that when the OK is given to return to the labs, you may check your suit into the laundry and check out a fresh set. Do not re-enter labs until staff have communicated that it is safe. Let staffers know if you have any work underway or in process, so they can prioritize tasks in bringing the labs back up. Response Procedures for Lab-only Evacuation: - Evacuate the lab immediately to the office area outside the lab. - Do not re-enter the lab until cleared to do so.
A lab-only evacuation should be called for any hazardous situation which is isolated to the lab and does not pose a health or safety risk to building occupants outside the lab. Such situations may include a chemical spill or unusual odor. Any other situation in which the health or safety of lab occupants may be of immediate concern warrants a lab-only evacuation. A laboratory evacuation may be called by an announcement over the PA system (red phones.) Anyone may call an evacuation. Unless specifically otherwise instructed by staff, you should respond as would for a building evacuation: Leave immediately through the nearest lab exit: do not take time to finish your tasks in the lab, remove your bunnysuit, or pick up your belongings. Meet in the office area outside the lab, for further instructions. Response Procedures: - Announce evacuation over the PA system (red phones). - Evacuate immediately to the office area outside the lab. - Do not re-enter the lab until cleared to do so.
This is by no means an exhaustive list of possible emergency situations. Please note that specific circumstances may dictate different procedures. But these describe resources and considerations for responding to emergencies.
Type of Emergency | Response |
Health Threatening Fire, toxic spills, gas leak, leave building and go to EAP#104, located on Jane Stanford Way, just past the water fountain on the sidewalk |
|
Major Earthquake |
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Life-Threatening Medical Emergency (if in doubt, treat as an emergency) |
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Non-Health Threatening Emergency (Building and facilities) |
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Electrical Power Outage
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Chemical Spill < 30ml |
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Spill > 30 ml or will take longer than 15 minutes to clean up |
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Odor in the Lab |
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General chemical safety training is required to access the following "wet lab" spaces: Cleanroom/L119, the MOCVD lab, L106 (ExFab Stinson), and rooms 155 (ExFab Mavericks) and 159 (ExFab Capitola).
Note:
Even if you do not intend to use any operations with hazardous gases and chemicals, anyone with access to these spaces must be trained to be aware of the hazards they present, the safety systems, and how to respond.
This space has fume hoods for chemical handling. Additional training is required to gain access to this space and is customized to accommodate each person's needs.
Safety training gains you access to lab spaces. For training on specific equipment and modules, consult the equipment table or any staffer.
Each chemical container is required to have a label, provided by the manufacturer, which in addition to composition, contains the following information:
- Precautionary Measures.
- One or more Statements of Hazard, which describe in more detail the hazard presented.
- A signal word, which is one of the following: “Caution”, “Warning” or “Danger”, indicating potential for hazard (in order of increasing potential hazard.)
- First Aid or other information (this may not always be present on the label.)
Remember, only chemicals in their original containers will have these labels. Chemicals that have been dispensed for use or into other containers may not have this information. Since gases are supplied remotely, their label information will not be handy. As a qualified user, it is your responsibility to know the chemicals being used at your station, and the hazards posed by each.
Chemicals manufacturers and distributors are required by federal law to provide safety information for each product. The Safety Data Sheet (SDS, once called “MSDS”) contains information on general composition, physical and chemical properties, toxicology, and storage and handling recommendations of each product. SDS documents for all the chemicals that SNF routinely stocks can be found on the SNF website. Labmembers wanting to bring in any new chemical or chemical mixture for use in the lab must provide an SDS as part of the New Process & Materials request.
SDS information is written without specific regard to application or context for use in research. So, make sure to consult with the website and staff for any questions about safety and use of these materials. You should know the main hazards, handling requirements, and disposal methods for any chemical you use in the lab.
The Stanford University Environmental Health and Safety EH&S department maintains an extensive website library on chemical safety. Included in the library is educational material on safety basics, such as how to decipher the terminology in an SDS form.
The website has lots of info about hazardous materials and their specific use in the lab, including: links to SDS sheets; lists of approved materials in the lab; and procedures for safely bringing in new chemicals and new processes. The website contains links to Operating Procedures for each tool (in the Equipment section) which includes safety information for the chemicals and other hazards at each station. The Processes section of the website includes much information about the standard use of many of the common chemicals found in the lab.
The gases, chemicals and materials used at SNF are categorized into six general chemical hazard classes: corrosive, oxidizer, air/water reactive, flammable, toxic/poison, and non-toxic, as detailed below. Many chemicals fall into more than one class. Safety policies on storage and use of chemicals begins with identifying the primary chemical hazard class.
or "caustic" damages or destroys living tissue, such as skin. Splashes in the eyes can cause blindness. Inhalation of vapors can destroy lung tissue. Corrosives include acids and bases. In case of localized external exposure, promptly flush the affected area with plenty of water, for at least 15 minutes. For more general external exposure, use a safety shower: remove clothing while showering and flush bare skin for at least 15 minutes. Exposure of corrosives to the eyes is extremely serious; flush immediately, either with a spray gun at your wet bench or the nearest eyewash station. Eyes should be rolled up and down, and side to side, continuously, to allow clean water to flush behind the eyeball. For any exposure to corrosives, get help. The victim should be taken to the emergency center for evaluation and treatment.
compounds have a pair of electrons, often due to the presence of a reactive oxygen atom. Examples of oxidizers at SNF include hydrogen peroxide, nitric acid, and sulfuric acid. Mixing an oxidizer with an electron-accepting, reducing compound, may result in an often violent reaction, possibly an explosion. Oxidizers should not be stored or mixed with flammables or combustible chemicals and materials.
compounds are generally concentrated acids or bases that rapidly generate heat and/or gas upon mixing with water. The primary hazard of water-reactive compounds is superheating of water. Explosion may result, sometimes delayed well after the addition of water, due to incomplete mixing. Never pour water-reactive mixtures directly into a sink drain. Instead, aspirate water reactive mixtures at wet benches; the high dilution factor and rapid mixing dissipates heat and prevents superheating. Concentrated sulfuric acid and piranha clean are examples of water reactive materials.
include most solvents, such as acetone, isopropanol, and methanol. The “flash point” of a flammable is the lowest temperature at which its vapor concentration in air can ignite. The source of ignition may be heat (such as a hot plate) or a spark (such as from an electrical tool). Because the vapors travel, the ignition source can be far away from the flammables container. To minimize hazards, always work well within the exhausted area of the appropriate bench (behind the red line). The air pulled into the exhaust area will keep the concentration of vapors below the flash point. Where possible, minimize the quantities of flammables used. Before working with flammables, always note the location of the nearest safety shower and fire extinguisher. Flammables should be stored in the designated flammables cabinet; no flammables may be stored in the lab. Flammables must be kept away from oxidizers.
A toxic material is one that has poisonous or harmful effects. There are formal, quantifiable definitions as to what comprises a toxic material and to what degree it is toxic. These definitions are based on lethal dosages for lab animals when administered orally or through inhalation.
A non-toxic material is one that is not likely to result in harmful effects with normal use.
Every chemical in the lab must be stored in the designated area appropriate for its hazard class. Each storage area is designed for safe storage of chemicals of a particular set of hazard classes (i.e., they are appropriately ventilated, chemically resistant, and built against the main physical hazards presented by the chemicals to be stored there.) Thus, it is a safety imperative that all chemicals in the lab be stored appropriately in one of these designated storage areas.
General use chemicals are stocked in these areas:
Ensure your safety and that of others when using these chemicals by following procedures for handling and transporting chemicals in the lab.
Labmembers may store chemicals for personal research use on request, provided it is registered in our Chemical Inventory and marked with a yellow label. Submit your request to snf-promcommittee@lists.stanford.edu
you should always do the following:
Training is required for any chemical handling in the labs. Once trained, you are responsible for safe use and disposal of waste. If you see chemicals improperly handled, you are responsible for following up with the individual or report to staff. Safety is everyone's responsibility. Improper disposal could result in explosion and injury. Policy violations may even result in lab shutdown. Therefore, take time to consider how to manage waste in your experimental plans. And remember that we all bear the economic and environmental costs; so please minimize the waste you generate. There are four ways of disposing of chemical waste; the safest method depends on the kind of chemical waste, as described below. If you have any questions about the best method for handling chemical waste, please reach out to staff.
The AWN system is a network of piping that runs from the labs into a central system of holding tanks, where the chemical waste is successively neutralized and diluted, before draining into the sewer system. Some wet stations are connected to the AWN system. Only standard inorganic, non-heavy-metal containing, liquid waste, can be drained into the AWN system.
Mixtures containing solvents, metals, fluorine, and solvents must NEVER be dumped into the AWN system. [Link to list of Palo Alto/ Stanford EH&S for specific]
Unless you are trained at a station that allows it, you must never put any chemicals into an AWN drain. If, by accident, such chemicals are poured into a processing module which normally drains into the AWN, do not drain. Instead, notify a staff member immediately, who will be able to arrange another method of disposal. When the AWN system is not functioning, the AWN alarms located throughout the lab will flash. When the alarm is actuated, do not operate any of the wet stations, as this means the facilities are out of compliance.
is a network of double-contained piping that runs from the labs to a central holding tank. Because high concentrations of fluorine are a health and environmental hazard, the HF drain system is separate from the AWN system, in order to ensure fluorine waste is kept out of the sewer system. Instead, waste collected in the HF tank is routinely collected to be treated off-site. Fluorine-containing chemicals that should be drained into the HF system include hydrofluoric acid, buffered oxide etchants (BOE's), ammonium fluoride, and any mixtures thereof. Some wet stations are connected to the HF drain system. Unless you are trained at a station that allows it, you must never put any chemicals into an HF drain. Do not dispose of fluorine-containing solutions into drains that are not labeled for HF waste. And because aspirators drain into the AWN system, do not aspirate fluorine-containing solutions.
Carboys, containers, and waste bins in the labs may be designated and labeled as Solvent Waste collection. Standard, non-halogenated solvent waste is collected into 2.5 gallon carboy containers (liquid waste) or in labeled waste bins (solid waste only, secured in zip-locked bags) at the solvent wet benches. The standard solvents are: methanol, isopropanol, and acetone. Standard solvent waste includes these chemicals and photoresist waste. Do not put halogenated waste into the solvent waste carboys or waste bins; instead, use Local Collection. All labmembers qualified for access to wet labs can make use of the standard solvents for cleaning samples, and so must dispose of liquid and solid waste accordingly.
Many chemicals used at SNF cannot be disposed of using the AWN, the HF drain, or the general solvent waste collection tanks. Local collection is performed at the "flexible" wet stations which have sufficient exhaust and deck space to support this. Only labmembers who are trained and qualified to use flexible wet stations and have privileges to the online Stanford EH&S hazardous waste tag system may use local collection.
must be collected locally, as these chemicals cannot go into the AWN.
Examples include: used gold or chromium etchants.
Prohibited heavy metals and other toxics include, but are not limited to, the following: Antimony, Arsenic, Barium, Beryllium, Boron, Cobalt, Gold, Manganese, Molybdenum, Selenium, Thallium, Vanadium, Cyanide, Formaldehyde, Phenols, any chemicals on the Federal List of Acutely Hazardous Chemicals or the California List of Extremely Hazardous Chemicals
are discouraged from use in the lab and some are banned.
Examples include chlorobenzene, TCA, borothene, and carbon tetrachloride. Halogenated organic waste must be treated by incineration at higher temperatures than for other wastes, to prevent the possible formation of highly toxic compounds such as PCB's and dioxin. So separate and properly label halogenated waste from other solvent waste.
and its processing by-products are toxic. All persons working with GaAs should develop especially good "housekeeping" habits and be constantly aware of how arsenic might be generated during processing. Avoid direct physical contact with GaAs and anything that comes into direct contact with GaAs. When breaking and scribing GaAs wafers, work under the designated exhausted hood deck and wipe down all surfaces afterwards to prevent spreading of GaAs dust. Follow handling and decontamination procedures at each equipment where GaAs processing is done. Any GaAs waste, no matter how small, must be considered hazardous, including GaAs-contaminated wipes and old proximity-cap silicon wafers. Place GaAs waste in an airtight zip-lock plastic bag and place in a hazardous waste bag. Label the waste bag as appropriate.
With the exception of using small amounts of alcohol for wiping down surfaces, chemicals must be used only at designated wet stations. All wet bench stations have the following features:
include all the WBClean, WBDecon, and WBResStrip stations which may be used only for processes and chemicals as described in the operating procedures for each station. Standard wet benches are designed to handle whole cassettes of wafers and have a range of semi-automated modules (hot pots, wet tanks, dump rinsers) for processing cassettes. Here are the main features of the Standard wet bench stations:
are the flexible wet stations, as indicated by "flex" in the station name (WBFlexCorr, WBFlexSolv). These are mostly manual stations that can be used for a broader range of chemicals and processes. Here are the main features of the flexible wet stations:
Beakers and other chemical containers may be used at these stations, but only for chemicals approved for use at the specific stations.
are absolutely required for each beaker or container with chemical, even for water. These forms are available in the lab and require the date, your contact info, the full name of the chemical, and its hazard category. An unlabeled or improperly labeled container of chemical is a violation of safety policy and grounds for loss of lab privileges.
Isopropanol and ethanol in labeled squeeze or spray bottles are the only chemicals that may be used outside of wet benches, for wiping and disinfecting surfaces. The bottles must be put away and stored at the solvent benches when not in use. Because of their high vapor pressure and flammability, they should be used only very sparingly outside of solvent wet benches. They should never be used at non-solvent wet benches nor near any electrical equipment.
Appropriate PPE is available near wet stations throughout the labs and must be worn when handling and transporting chemicals. Chemicals should be transported using the appropriate transfer carts (white polypropylene for corrosives/oxidizers; metal for solvents/resists/developers.) Chemicals must never be transported by hand, even hand-carrying a beaker of water.
For specific procedures on transporting acids or bases see Appendix 5.6.
For specific procedures on transporting solvents see Appendix 5.7.
Chemicals can behave very differently when heated or mixed with other chemicals and present completely different risks. You are performing a non-standard process if you are heating a chemical which is not normally heated, or mixing chemicals that are not normally mixed -- even if the chemicals are normally stocked in the lab. The following hazard classes must never be
mixed together:
Personal protective equipment (PPE) is required whenever handling or transporting chemicals in the lab. PPE required depends on the chemicals being used. Below lists the type of protective gear, in addition to your safety glasses and appropriate lab wear, that is generally used for various chemical types. This is only a guideline; the operating procedures for each wet bench should serve as the final word. Remember, you are responsible for your own safety, and that of others around you. SNF provides you with information, recommendations, and necessary resources for you to be able to do your work safely. It is up to you to ensure that you take appropriate precautions for your safety and your fellow labmembers.
We are required to maintain an up-to-date list of the names and amounts of all hazardous chemicals and materials in the lab. With every chemical or material brought into the lab, we need to ensure there is:
- a safe way and place to store it
- a safe way to use it
- a safe method of disposing of it and its byproducts
- a way to prevent cross-contaminating other labmembers' work
All process chemicals and materials used in the lab must be approved by the Prom committee before use. New chemicals and materials are approved for a given process and may be on a case-by-case basis. ProM requests are also required when using standard chemicals, but in a non-standard way, such as heating or new mixtures. When in doubt, consult with a staffer. To register a new chemical, material, or process, submit a ProM request.
(with identification of owner, contents, and other safety info, as per section 4.4). This is an ever-changing research environment with a lot of chemicals and materials -- we need your help to keep track of them all.
Because SNF is a community of researchers, we all need to be extremely considerate of potential problems posed by the hazards of new materials and how they will affect the research of others. The SNF website should answer the most common questions and concerns about which chemicals and materials and where their use is acceptable in the lab, but it is far from comprehensive. Please take time to carefully consider the process flow of your experiment and how it might affect other labmembers and other downstream processes. If you have any concerns, contact the Prom Committee (snf- promcommitte@lists.stanford.edu), who would be glad to discuss.
Acetone, isopropanol, and methanol may be found in the solvent wet benches. Acetone is often used to dissolve photoresist and other polymers. Isopropanol and methanol are often used for cleaning. These chemicals are all flammable solvents with low flash points, which means they can be easily ignited at room temperature and, therefore, pose significant fire hazard. Thus, solvents should not be used on or near hot plates or near any electrical system. Solvents may also ignite or explode when brought into contact with chemical oxidizers (such as many acids) and so should not be mixed with, nor collected in the same waste container as these compounds. Standard solvent waste should be disposed of in the solvent carboy or collected locally. These and other solvents must be stored in the designated flammables cabinet in the service area and may be transported in the lab only if carried in metal carts. Solvents may be used only in designated solvent hoods.
(such as chlorobenzene, trichloroethylene [TCE], and methylene chloride) may be present in some special resist processes, although these have been phased-out of general use. Long term, repeated exposure to some chlorinated solvents is correlated to cancer and liver and nerve damage. Because of environmental hazards, chlorinated solvent waste must be collected in a waste container, separate from other kinds of liquid solvent waste.
Methyl- and ethyl- glycol ethers may be present in some photoresists. These have been implicated in reproductive problems in semiconductor workers. SNF does not stock chemicals which contain these, but instead use ethyl lactate and propyl- glycol ethers which are the accepted replacements. However, some specialty chemicals, such as imported high performance resists, may contain methyl- or ethyl- glycol ethers. Glycol ethers may be referred to generically as "Cellosolve", but the following names also refer to glycol ether compounds: Methyl Cellosolve, 2-methoxyethanol, Ethyl Cellosolve, 2-ethoxyethanol (2EE), Ethylene glycol mono ethyl ether. Acetate salts of glycol ether compounds may also appear in some specialty photoresist formulations as: Cellosolve Acetate, Ethyl cellosolve acetate (ECA), Ethylene glycol mono ethyl ether acetate, 2-Ethyoxy ethyl acetate. Environmental monitoring studies done of the SNF indicate that there is no risk of significant exposure of these compounds, as long as handling of photoresists takes place only in designated exhausted work areas. As a labmember, your responsibility is to always observe proper chemical handling practices, and to make sure that the people working around you do so, as well.
All peroxides are highly oxidizing materials; energy is released when they are reacted. Some peroxides are unstable, and can explode. 30% hydrogen peroxide in water is stocked the lab. Extreme care should be used in mixing solutions containing peroxides. Peroxides are incompatible with all forms of organic solvents and flammable materials.
The heated mixture of concentrated sulfuric acid and 30% hydrogen peroxide, commonly referred to in the semiconductor industry as "piranha clean", is an extremely aggressive oxidizer and extremely corrosive and used for removing photoresist, contaminants, or to etch metals. The proportions of sulfuric acid and hydrogen peroxide used will depend on the particular wet bench and application. The piranha solution self-heats when mixed and immediately destroys organic materials it contacts (photoresist, cleanroom wipes, vinyl or latex gloves, skin.) Piranha vapor is extremely caustic, so the piranha mix should be used only under an exhaust hood. Boiling piranha spatters, so always wear protective gear when working near a hot pot. Piranha is incompatible with all solvents and flammable materials. It reacts violently when mixed with base. Do not add water directly to piranha to try to cool it; sulfuric acid is water reactive, so adding water will cause heating (not cooling!) and can lead to an explosion. General Information on Piranha Solutions is available on the EH&S reference site.
is an oxidizer and is also water reactive (heats upon addition of water). Nitric and acetic acids are components of pre-mixed Aluminum etchants. All oxidizers should be kept away from solvents, bases, and flammable materials.
Hydrofluoric acid (HF) and related fluoride-containing mixtures (such as ammonium fluoride or BOE) are among the "high hazard" materials carefully monitored by Stanford EH&S. Concentrated HF produces extremely painful, deep tissue burns. Lower concentrations of HF are particularly insidious, as the initial contact may produce no pain at all, although tissue damage may continue over days following exposure. It can be easily absorbed through skin and has a high vapor pressure, so can be easily inhaled. HF can cause electrolyte imbalance that can lead to cardiac arrest and death. If you will be working with HF and fluorine acids, make sure to read the EH&S Information on Hydrofluoric Acid reference.
and Pad Etchants are pre-mixed solutions of HF and buffer, or ammonium fluoride (NH4F). Although ammonium fluoride is a neutral salt of HF, it readily dissociates to yield fluorine ions, and so presents nearly the same hazard as HF. All BOE's contain nearly the same total fluorine as concentrated 49% HF.
by providing calcium ions to bind fluorine. In cases of exposure to skin, calcium gluconate gel must be applied immediately to the area of contact. For systemic exposure, calcium gluconate is delivered by injection, by a healthcare professional. Tubes of calcium gluconate gel, along with instructions for use in case of contact exposure, are mounted to the front panel of every wet bench where HF and fluorine-containing chemical mixtures are used. More about emergency treatment of HF exposure can be found in the EH&S Information on Hydrofluoric Acid reference.
Alkaline compounds, or bases, are the chemical opposite of acids, and may react violently when mixed with them. They are most commonly used in the lab in lithography and etch. Alkalis are caustic, so protective gear should always be worn when working with them to prevent contact with skin and eyes.
Heated solutions of 25%-30% alkali solutions, such as potassium hydroxide (KOH) and tetramethyl ammonium hydroxide (TMAH) are as anisotropic etchants of silicon. These etchants may be used only at the wbflexcorr stations. TMAH is a "high hazard" material (see below) and so requires additional controls.
Tetramethyl ammonium is a nerve agent and its hydroxide form is easily absorbed through skin. Deaths have resulted in an industrial accident where 25% TMAH spilled onto workers even though they rinsed within a minute of exposure. TMAH is used at lower concentrations (2-3%) in most photoresist developer solutions. Health effects have been documented for large area exposure at these concentrations, so PPE should always be worn when handling developer solutions directly. All labmembers working with this chemical must review the TMAH Fact Sheet. Use of 25% TMAH requires special training and advance arrangement with wet bench staff.
( PRS 1000, PG Remover and related chemicals) These are organic base mixtures, which are used for removing photoresist from wafers containing metal films (which are corroded by conventional piranha clean.) Unlike other acids and bases used in the lab, these strippers are not water-based and are combustible; by some criteria, they may be considered solvents. These strippers must never be directly mixed with strong oxidizers.
Most hazardous process gases are located in reinforced storage vaults away from the lab. Gases are stored by chemical class in individual gas cabinets and are monitored by an automated toxic gas detection system. Nitrogen, argon, hydrogen and oxygen, are kept in liquid form in large storage tanks outside the lab. Process gases are delivered to the lab through a series of valves, regulators and flow control systems. Few gas bottles are stored in the lab; those that are must be secured.
Because of the hazards present, only trained and qualified staff are permitted to install, handle, and disconnect or change out gas cylinders. Hazards include the following.
consists of a network of remote sensors located throughout the lab and the gas pads and vaults. Depending on the sensor, when triggered, the system launches a preconfigured sequence which may include the following actions: 1. activation of gas shut-off valves; 2. activation of audible alarms; 3. notification of the appropriate response teams. This automated function ensures the appropriate response will be always taken in the event of a toxic gas emergency and, thus, enables the lab to run 24 hours/day, 7 days/week.
These gases will spontaneously ignite in air within a critical concentration range.
These gases described here are severe pulmonary irritants and acute systemic poisons. Overexposure can cause either sudden or delayed death due to lung destruction. Although each has a characteristic smell, the odor threshold is not much lower than the toxic exposure level. The gases described here are mixed at low concentrations in carrier gases (silane, hydrogen, or nitrogen) and used as film dopants in LPCVD and Epi2 systems.
These gases are considered non-toxic because they do not generally pose an immediate risk to health and safety. However, they can be asphyxiants and may pose other health risks at high concentrations or with long-term exposure.
Nitrogen, argon, helium, hydrogen, and oxygen are stored in liquid form outside the lab and are evaporated to be delivered to the lab in gas form. LN2 should not be used in an enclosed space because of the risk of asphyxiation. LN2 can also burn tissue on contact, so protective gear must be worn whenever handling.
Described here is a general list of criteria of cleanroom- and non-cleanroom-compatible materials. These guidelines are subordinate to the "Acceptable Materials" policy.
• Cleanroom notebooks and cleanroom paper (available in Stores.)
• Wafers and tweezers, in labeled boxes.
• Pens (preferably, ball-point).
• Materials with smooth, hard surfaces, which can be cleaned with alcohol wipes.
• Wood pulp-based paper products, which includes regular paper, tissues, cardboard, books, and magazines.
• Styrofoam products.
• Any powders.
• Erasers, pencils, felt-tipped pens (other than Sharpie markers).
• Anything that can easily shred or aerosolizes; i.e., anything that may serve as a source of particles.
Wafers should not be touched with gloved hands, even clean vinyl gloves (which have plasticizer residue). Good, careful handling practices will help ensure wafers are undamaged and minimize the possibility of contamination which could adversely affect device processing and performance.
These rules are based the principles of Safety, Community, Respect, and Integrity. EVERYONE in the lab community, lab and staff members, and visitors alike, is expected to abide by these principles. As a teaching organization, we understand that the vast majority of violations are simply mistakes, best addressed through retraining or mentoring; intentional violations are are rare addressed on the strictest terms. We believe the greatest resource in our lab is the lab community and strive to foster a culture that places high value on mutual respect and personal and scientific integrity.
is of the utmost priority. Community members must behave in a safe, conscientious, and professional manner in all lab activities. Each individual is responsible for his/her own safety—AND the safety of his/her fellow labmembers. We recognize the need to test and develop new ideas and capabilities; your responsibility is to work with staff and other knowledgeable people to ensure that any new procedure/chemical/equipment is introduced in a safe manner. It is also your responsibility to address any safety concerns you may have with fellow lab and even staff members. The best response is to address the issue directly with the person concerned. If this is not practical, you should report the concern to the staff person responsible for the station in question or senior management, as appropriate. To report any potentially unsafe conditions or practices, or to offer suggestions for improving safety, you can contact any staff member or direct an email to snf-safety@lists.stanford.edu
In a shared lab, everything each individual does can and will affect others, thus, it is everyone’s responsibility to minimize the impact of activities that can adversely affect others and contribute positively toward the good of the community. Remember, this is YOUR lab.
All members of the SNF Lab community are expected to abide by the Statement of Respectful Workplace: “The Stanford Nanofabrication Facility is committed to providing an environment that is conducive to high-quality research, learning and productivity. Effective interpersonal communication is essential in this environment. As such, all members of the community (students, industrial visitors, staff and faculty) are expected to act in a manner based on courtesy, civility, mutual trust and respectful communication. All members of the community should treat one-another with an awareness of the potential impact of their interactions, and strive to conduct themselves at the most respectful and professional level.”
Locations: Video cameras are installed in areas related to SNF operations:
Purpose: Video monitoring will be used as follows:
Use and Authorization:
This document describes the procedures for entering and exiting the cleanroom, including the gowning protocol. These procedures are designed to minimize the potential for transferring and generating particulate matter, which could adversely affect the lab.
Qualification Checklist
All SNF labmembers must demonstrate or describe the following:
Make sure you are wearing appropriate attire:
Before working with wafers, put on vinyl gloves over the latex (or vinyl) gloves.
Change vinyl gloves frequently
1. whenever getting ready to handle, transfer, or inspect wafers;
2. whenever any contamination is suspected. Vinyl gloves are available in the gowning room and throughout the lab.
Described here is a general list of criteria of cleanroom- and non-cleanroom-compatible materials. These guidelines are subordinate to the "Acceptable Materials" policy.
The following materials are generally acceptable to bring into the cleanroom:
The following materials are not considered cleanroom-compatible:
(Updated Jan 2024)
Transfer Carts:
Protective Gear: Should be worn whenever handling hazardous chemicals.
Procedures:
(Updated Jan 2024)
Transfer Carts:
Procedures:
1. Chemicals used in the lab must be Prom committee approved. Approval requires a list of tools which will be exposed to chemicals either directly or indirectly (i.e., present on substrates), the process used (heating, mixing, recipe, etc.), and provisions for storage and waste disposal.
2. Chemical containers must be labeled and barcoded. Include chemical name/composition, your contact info, and date. Obtain a yellow label and barcode from a staff member. The tradename for a chemical mixture can be used as long as the MSDS is on file with Prom committee.
3. No chemical powders or crystals are allowed in the cleanroom. Powders and crystals can be dissolved and mixed into solutions in the Utility/Wafersaw room before being brought into the cleanroom.
4. Use secondary containment when transporting chemicals ANYWHERE. 5. Chemicals may NOT be brought through the gowning room.
6. To bring a chemical into the lab, you may either:
a. Contact a staff person who will place your chemical in the chemicals passthrough; or,
b. Place your chemical in the service area, using the door at the back of the lab. You may then gown up to retrieve your chemical. To do this, you must:
• Use secondary containment (cart)
• Label your chemical container with contents, your contact info, and date. This MUST be visible on the outside of the container (and on the outside of secondary containment, if used.)
• Place it in appropriate storage as soon as possible. Remember: unattended and/or unlabeled chemicals WILL be disposed of.
• Note: the service door is locked after hours.
2. Remember to discard your chemical when you are finished with it in the appropriate manner.