ESD Tutorial Includes:
ESD Basics How ESD affects electronics components Protecting against ESD ESD protected area ESD workbench ESD work mat ESD wrist strap ESD clothing ESD storage ESD process ESD on a budget Design to combat ESD
It is very important for any electronics manufacturing, service, repair or any other area dealing with electronic components and circuits to have an ESD protected area of some form.
Of equal importance is to have a control process or programme which sets out how it is used. It is vital that the ESD protected area is used in a way in which it is able to perform. Everything from the way in which it is used, to the testing of wrist straps and other equipment to ensure everything is operational is required.
An ESD control programme will address all the areas of ESD relevant to the particular area, and in this way the ESD control process will address all the relevant problems.
The ESD control process must be implemented in such a way that all people in the relevant areas adhere to the standards and procedures. Only in this way will the ESD control mechanisms work effectively.
When considering setting up an ESD control process or ESD program, it is essential to consult the ANSI/ESD "20.20 standard. This standard is internationally recognised and has been developed by ANSI (American National Standards Institute) and the ESD Association.
The ANSI S20.20 standard covers the requirements necessary to design, establish implement and maintain an ESD control program. It is aimed at organisations that manufacture, process, test, repair or carry out any activity with electronics equipment.
Having been prepared by the industry experts, it provides the authoritative view on setting up and maintaining an ESD control program.
Management backing for an ESD control process
In order to put the ESD control process in place there are a few fundamental steps that must be taken. By ensuring that the proper foundations are in place, the ESD control process itself will be able to be rolled out more smoothly and effectively.
The first key step is to ensure that senior management are behind the ESD control programme. Without senior management backing any initiative of this nature is bound to founder. The implementation of the ESD control process will result in costs, and it is necessary that management are aware of these from the outset. Preparing them from the beginning will enable them to be prepared. With their backing it will be possible to have authorisation for the spend in terms of capital outlay, as well as other on-going costs including training.
Fortunately the case for installing and ESD control process is well proven. Any electronics manufacturing or service organisation will need to employ ESD control precautions. Without them quality will be poor, and in addition to this many customers will not want to deal with a company that does not have a good ESD process in place. These facts are well documented and can easily be presented to management if any problems occur.
With the backing of management in place, it is then necessary to secure the cooperation of any associated departments who may be directly or in-directly involved in the set-up, use and maintenance of the ESD control programme.
ESD control process fundamentals
In order to be able to set an ESD control programme in place, it is necessary to start with the fundamental requirements. These have to be identified as the fundamental requirements, but in addition to this, the ESD control process needs to be tailored to suit the individual area in which it will be implemented. However the following form key elements in any ESD control process:
- ESD protected area: One of the key elements is to create an EPA, ESD protected area. This has already been covered in another page in this tutorial, and reference can be made to that page.
- Signs and notices: The EPA should be well highlighted with signs to let people know they are entering an ESD protected area. It also acts as a constant reminder about conforming to the ESD protective measures.
- ESD process: Creating the physical area in which the static sensitive devices are to be handled needs to be supplemented by a written process detailing how the EPA will be used and run. This is just as essential as the EPA itself.
- ESD training: ESD training is a further key point. All staff must be trained to inform they what ESD is, its importance, how ESD can be combated and how the equipment in the EPA will be used. All staff that are likely to use the EPA must be completely trained and have "bought into" the process. By understanding what is happening and the need of ESD control, they will be more willing to follow the processes and procedures required.
Writing an ESD control process
An ESD control process defines how the EPA is set up, run on a day to day basis, and its maintenance. It should contain the "do's and don'ts and inform all who use it how it is to be used and what they should do.
An ESD control programme or ESD control process should define many elements. It can be split into two main elements:
- Definition of the physical elements within the EPA
- Definition of the way the EPA is used and the processes or actions required
In this way the ESD control process defines the equipment and the way it is sued. By keeping them all in one document together, and any changes that might be required can be reflected in both plant and process at the same time.
In terms of the plant or equipment that is required the items that might be covered will essentially form the EPA and should include the following: ESD workbenches, ESD wrist straps, ESD clothing, ESD shoes, ESD flooring, ESD chairs, ESD storage and packaging, ESD signs, humidifiers and anything else required for the EPA. It should also define the overall specifications required for any items within the EPA. Products should be defined so that the same products are used throughout and they are to the required standard.
The ESD control process document should detail how people should work within the EPA and any other actions that must be undertaken.
- Basic instructions on using the system: The control process must define how the EPA will be used by those in it, detailing items such as the wearing of ESD clothing, ESD footstraps, or ESD shoes, etc. It should also include a mention of the fact that unwanted insulating materials should not be brought into the EPA. This should include personal belongings such as bags, etc. as these are likely to contain static carrying insulators.
- Training: The ESD control process should define who should be trained, to what level and how often. For an effective ESD process, all staff should be trained to a certain level to make them aware of the reasons for the EPA, how the EPA works, and how they should use items within the EPA and any special precautions to be taken.
- Testing and maintenance: With constant use, items within the EPA will fail. In particular items that are flexed such as the leads for ESD wrist straps may break and so forth. Often ESD workbenches have monitors fitted that continuously monitor the connectivity. Also other facets such as cleaning are important. Dirt build up on workbenches will cause the conductivity to fall and the static dissipative surface will become less effective. Flooring must also be cleaned. Any cleaning methods will need to be carefully specified so that the basic static dissipative properties of any surface that is cleaned are not impaired. Care should be taken when selecting any cleaning agents. They should not be abrasive so they damage any static dissipative surfaces, and some solvents may attack the surfaces and should not be used.
Any testing to be undertaken should be defined. Test equipment and the test method should be accurately defined. In addition to this routine audits should be included in the maintenance schedule so that standards are maintained.
The ESD control process should also include a regular audit capability. This should comprise formal audits to ensure that the process is being adhered to and that short-cuts are not being taken. It may also highlight new ideas that could be adopted into the process to bring about improvement. In addition to the formal audits, reviews should be scheduled periodically to look at process improvements. In this way, the ESD control process can be updated to reflect both changes in the environment or work being undertaken and also changes in ESD control technology. This will ensure that the ESD control process is always relevant and up to date.
A further element of any ESD programme is to ensure the safety of the people working in the area. There are possible safety implications of the use of some items such as ESD overshoes, ESD footstraps. Also electrical safety must be considered.
As a result, safety should be considered within the ESD control process. It may be necessary to carry out a risk analyses, assessing what risks there may be and how each risk may be reduced to an acceptable level.
By considering safety and risk at the conceptual stages of the ESD process, risks can be reduced or overcome and a safe operating environment can be assured.
The ESD control process can be written in such a way that it is not a document that is stored away, but one that provides useful and helpful guidance. By implementing it in an imaginative way, people can have access to the guidance and be able to follow what is required of them to ensure that the ESD control is successfully implemented.
The ANSI/ESD S20.20 standard provides an excellent basis for the control process and using the standard it is possible to gain guidance on all aspects of developing the ESD control programme. It is also necessary to gain the support of management for the area directly affected by the ESD control process as well as the management and people within other related departments.
Once in place the ESD control process should be monitored using metrics and then it will be possible to see those elements that are working and those that are not. The process can be updated accordingly.
With all these elements in place ESD control should be successfully maintained.