ESD wrist straps are the first layer of ESD protection mechanism commonly used by the electronic industries to protect ESD sensitive parts or assemblies from ESD damage.

For critical environments such as hard disk drive, semiconductor and flat panel display manufacturing, it is very important to ensure the personnel who handle the ESD sensitive items are truly grounded.

Getting the wearers connected to the ESD wrist strap constant monitor is commonly practiced by most ESD Coordinator to give a real time indication that the wearers are connected to ground.

Does the ESD Wrist Strap Constant Monitor Meeting Your Company’s Expectations?

While there are many brands and types of ESD Wrist Strap Constant Monitor available in the market place, it is recommended to consider the following before buying the unit.

• Get a sample of the ESD Wrist Strap Constant Monitor from your nearby supplier

• Check its Technical Specification and analyze whether it both meets the ESD standard and your company expectations

• Perform functional test :
• Wear the ESD wrist strap and connected it to the ESD Wrist Strap Constant Monitor
• Check whether the light indicator illuminates when your wrist strap band firmly snug against your bare skin and the wrist strap cord is connected to the ESD Wrist Strap Constant Monitor
• Check whether the light indicator illuminates when you wear the wrist strap band over your ESD garment

• Without wearing the wrist strap and leave the wrist strap cord remains connected to the ESD Wrist Strap Constant Monitor
• Check whether the light indicator illuminates when your curl up the wrist strap cord

• Measure your body voltage by using a Charge Plate Monitor which is connected to a Graphical recorder or by using Prostat PGA 710 Auto Analysis system while wearing the wrist strap and remains connected to the ESD Wrist Strap Constant Monitor

• Check the reliability of the ESD Wrist Strap Constant Monitor whether it is a battery powered or AC powered unit

• Review the periodic testing and calibration requirements from the manufacturer of the ESD Wrist Strap Constant Monitor

A functional ESD Wrist Strap Constant Monitor is the unit where the light indicator illuminates only when the wrist strap band snug firmly against the wearer’s bare skin and with the wearer remains connected to the unit.

When you see the light indicator illuminates even without you wearing it or when you wear the wrist strap band over your glove or ESD garment, it is time for you to stop and think whether you should go ahead invest on the unit.

It is far better to remain checking the functionality of ESD wrist strap with the conventional ESD wrist strap checker than to invest on something that give you a faulty indication.

After working for so long as an ESD Coordinator in your organization, do you see yourself as a competent ESD Coordinator?
A competent ESD Coordinator is someone who can solve any problems associated with ESD by using his knowledge and experience.

However without proper knowledge , an ESD Coordinator would not be able to know what to do particularly in solving a new problem just encountered in the manufacturing lines.

To be a competent ESD Coordinator, he has to be fed with the correct technical information pertaining to Static Electricity and Electrostatic Discharge(ESD), which can be achieved through his working experience and/or through a training program.

To shorten the learning curve, an ESD Coordinator can attend an ESD training from any approved ESD training centers.
A training without a comprehension test, would not be able to validate if the ESD Coordinator is competent in terms of his Electrostatic knowledge.
Getting an INARTE ESD Certification is a recognized way where the ESD Coordinator can get a third party to endorse his competency in terms of Electrostatic knowledge.

Though there may be more than one approved INARTE ESD Certification Test centers/providers and/or ESD Training centers/providers in your area, ESD Coordinator may need to choose the correct ESD Training provider.

A competent ESD Trainer is a someone who does not only has a real passion in the field of Static Electricity and ESD but also is a someone who has a third party endorsement on his competency on the subject of Electrostatic.

Wait no more and start to get yourself certified as an ESD Engineer or professional ,not only it will help yourself but also your organization you are working for. Your organization’s customers will be more confident and at ease when they know they have a competent ESD Engineer caring for their ESD Sensitive products.

An ESD Coordinator has to know the ESD sensitivity level of the ESD Sensitive (ESDS) electronic devices being handled or processed to ensure the ESD processes that he sets up for his ESD Control Program is functioning as required and is not creating any ESD damage to the ESD sensitive parts.

ESD Association (ESDA) has issued an ESD Technology Roadmap on 4-March 2005.
This ESD Technology Roadmap provides ESD sensitivity trend for electronic devices for
Human Body Model (HBM), Machine Model (MM) and Field Induced Charge Device Model (CDM) for majority of CMOS devices (including RF).

The ESD Technology Roadmap shows ESD Sensitivity level trend only up to year 2010,
and it will only be valid for reference until end of next year.

Up to year 2010, the ESD Coordinator has to ensure his ESD personnel grounding processes are generating less 100 Volts HBM, machine parts that are in contact with ESD sensitive devices are grounded at all times, voltage induced on the ESD Sensitive parts is less than 50 Volts.

ESD Coordinator has to ensure he has all the necessary ESD equipments in order to perform ESD assessment on the ESD processes in the electronic manufacturing lines.

Some of the required ESD Equipments are:

• ESD Charge Plate Monitor with a graphical recording device or a ready made Human Body Voltage Measurement System
• ESD ground meter
• ESD Contact voltmeter

As years go by, the electronic device is required to perform faster, getting smaller and denser.
These features make the electronic devices become more vulnerable to ESD damage in years to come.

What would be the new control limit like for HBM, MM and CDM for year 2011 and beyond?
Would the control limits for all the three ESD damage models remain unchanged for year 2011?

The ESDA has a job to do.
The ESD Technology Roadmap is about to reach its final year next year.
It is time for it to be revised and republished.

As years pass by, new ESD technology and methodology are churned out by ESD industry experts/researchers with the intention to help ESD coordinators/specialists in their grueling ESD problem analysis and solving.

To investigate any ESD problem, we will need to have a systematic approach of analyzing the ESD problem.

We will have to start from the very beginning of a process chain of where the ESD sensitive device is first handled.
In a typical Printed Circuit Board Assembly manufacturing environment, a process chain will look something like this.

Incoming -> Store -> Kitting -> Screening ->Pick and Place -> Reflow -> Cleaning -> Backend soldering -> Testing -> Inspection -> Packing

Investigation shall start with how the ESD sensitive device is being handled in each process in the process chain.
Auditing alone to check for ESD compliance is insufficient to make conclusion that the process is not the source of ESD problem.
A fact finding approach is more appropriate to investigate the ESD problem.

Before start collecting data, we need to understand the ESD failure/damage models:
• ESD HBM damage model
• ESD MM damage model
• ESD CDM damage model

For each of ESD damage model, we will know what type of data to be collected.
• HBM damage model : we will have to measure human body voltage on personnel
• MM damage model : we will have to measure the grounding resistance of conductive elements of a manufacturing/test equipment that made contact with ESD sensitive device
• CDM damage model ( Field Induced model ) : we will have to check the electrostatic field voltage of the area where ESD sensitive device might pass through
• CDM damage model (Charged Package model): we will have to check the voltage on the conductive elements of the ESD sensitive device/assembly

After knowing the type of data to be collected, now we will have to prepare the ESD analysis tools. Examples of ESD Analysis tools are as follows:

• Prostat Auto Analysis System (PGA 710), analysis tool will be very handy to measure the human body voltage
• A normal digital multimeter or better still a true ground meter such as Ground Pro will be handy to measure the equipment grounding resistance
• A static field meter will be able to check for electrostatic field voltage
• A high impedance Contact Voltmeter such as Prostat CVM-780 Contact Voltmeter will be handy to measure voltage on the conductive element in ESD device/assembly/equipment

Based on ESD Technology Roadmap issued in year 2005, any ESD process in the manufacturing lines shall be controlled as follows through year 2010.

• Human body voltage on personnel shall be less than 100Volts
• Conductive elements of equipment shall be grounded ( or less than 10Volts)
• Voltage on ESD sensitive devices shall be less than 50 Volts

Measure the voltage on personnel, conductive elements of equipments and ESD sensitive devices at each process in the process chain will tell us whether the ESD sensitive device’s withstand voltage has been exceeded . If the ESD withstand voltage of the ESDS device is exceeded, that will point to the root cause of the ESD problem.

The importance of having a proper ESD audit checklist is undeniable.
The ESD Audit checklist is created with the intent to guide and act as reference for the auditor during the audit.Without a proper ESD audit checklist, the auditor may accidentally omit auditing a particular area or item which could be critical in the ESD Control program of the organization.

There are many ways where ESD coordinator could establish his ESD audit checklist.
The simplest way to create an ESD audit checklist is create checklist based on requirements disclosed on the ANSI/ESD S20.20 standard.

By adopting this simple method of creating ESD audit checklist, the ESD coordinator would at the same time working on and addressing the gap analysis of his ESD Control program plan against the ANSI/ESD S20.20 standard requirements.

It is an effective killing two birds with one stone practice which any ESD coordinator could practice and use it as a means to continually improve his ESD Control program.

A good ESD audit checklist should entail both the verification on the ESD control technical elements compliance as well as the generic esd control compliance required by the ESD control program plan of the organization.

The ESD audit checklist is the heart of any ESD audit and as such it should be established correctly in the first place to ensure the effectiveness of the planned ESD audit.

ESD coordinator should spend some time in creating the ESD audit checklist and continuously improve it when necessary.
By doing so, the effectiveness of the ESD control program of the organization can be monitored correctly.

An ESD Coordinator plays a big role when it comes to establish an ESD Control program for his or her organization. The ESD Coordinator must be well equipped with ESD knowledge and know how before he or she can carry his or her duties well. One of the things that the ESD Coordinator must know is to understand the ESD documents and ESD standards before setting up the ESD Control program.
The ESD documents can be typically classified into four categories such as:
•Standard
•Standard Test Method
•Standard Practice
•Technical report

Standards are ESD document that specify ESD requirements to be met by an ESD product, ESD material, system and process which are required in establishing an ESD Control program. ESD Standard begins with a prefix S such as the following:
ANSI/ESD S1.1: Wrist strap
ANSI/ESD S4.1: Work surfaces – Resistance measurements
ANSI/ESD S6.1: Grounding
ANSI/ESD S8.1: ESD awareness symbols
ANSI/ESD S20.20: Standard for the development of an ESD control program
ANSI/ESD S541: Packaging materials for ESD sensitive items
ANSI/ESD S7.1: Floor material – Characterization of materials

Standard Test Methods are ESD document that specify standardized test method which produce reproducible test results for evaluating an ESD product, ESD material, system and process that are required in establishing an ESD Control program. ESD Standard Test Method begins with a prefix STM as the followings:
ANSI/ESD STM2.1: ESD garments
ANSI/ESD STM3.1: Ionization
ANSI/ESD STM4.2: ESD Protective Work surfaces – Charge dissipation characteristics
ANSI/ESD STM5.1: Electrostatic discharge sensitivity testing – Human body model – Component level
ANSI/ESD STM5.2: Electrostatic discharge sensitivity testing – Machine model – Component level
ANSI/ESD STM5.3.1: Electrostatic discharge sensitivity testing – Charged device model (CDM)—Component level.
ANSI/ESD STM9.1: Resistive characterization of footwear (exclude heel strap and toe Grounders)
ANSI/ESD STM11.11: Surface resistance measurement of static dissipative planar materials
ANSI/ESD STM11.12: Volume resistance measurement of static dissipative planar materials
ANSI/ESD STM 11.13: Two point resistance measurement
ANSI/ESD STM11.31: Evaluating the performance of electrostatic discharge shielding bags
ANSI/ESD STM12.1: Seating – Resistive characterization
ANSI/ESD STM13.1: Measuring electrical potential from electrical soldering/desoldering hand tools
ANSI/ESD STM97.1: Floor materials and footwear – Resistance measurement in combination with a person
ANSI/ESD STM97.2: Floor materials and footwear – Voltage measurement in combination with a person

When the test method does not have the capability to produce reproducible test results, the ESD document is then classified as Standard Practice and this ESD Standard Practice begins with a prefix SP as the following:
ESD SP3.3: Periodic verification of air ionizers
ESD SP9.2: Foot grounders – Resistive characterization (exclude static control shoes)
ESD SP10.1: Automated handling equipment (AHE)
ESD SP14.1: System level Electrostatic Discharge simulator verification standard practice
ESD SP5.4: Latch up sensitivity testing of CMOS/BiCMOS Integrated Circuits and Transient Latch up testing – component level supply transient stimulation
ESD SP5.5.1: Electrostatic Discharge sensitivity testing Transmission Line Pulse (TLP) – Component level
ESD SP5.3.2: Sensitivity testing Socketed Device model (SDM) – Component level
ESD SP15.1: In use resistance testing of gloves and finger cots

Technical reports are ESD reports that provide technical and informational reference on a specific ESD material, product, system or process. This ESD reports begin with a prefix TR as following:
ESD TR 20.20: Handbook for the development of an ESD Control Program
ESD TR53: Compliance Verification of ESD Protective equipment and materials
ESD TR50.0.01: Can Static Electricity Be Measured
ESD TR50.0-02: High Resistance Ohmmeters–Voltage Measurements
ESD TR15.0.01: ESD Glove and Finger Cots
ESD TR13.0-01: EOS Safe Soldering Iron Requirements
ESD TR2.0-01: Consideration for Developing ESD Garment Specifications
ESD TR2.0-02: Static Electricity Hazards of Triboelectrically Charged Garments
ESD TR14.0-01: Calculation of Uncertainty Associated with Measurement of Electrostatic Discharge (ESD) Current
ESD TR5.3.2-01: Socket Device Model (SDM) Tester
ESD TR5.4-01: Transient Induced Latch-Up (TLU)
ESD TR5.3.2-01: Socket Device Model (SDM) Tester
ESD TR5.4-02: Determination of CMOS Latch-up Susceptibility – Transient Latch-up – Technical Report No. 2
ESD TR10.0-01: Machine Model (MM) Electrostatic Discharge (ESD) Investigation – Reduction in Pulse Number and Delay Time
ESD TR55.0-01: Electrostatic Guidelines and Considerations for Clean rooms and Clean Manufacturing
ESD TR1.0-01: Survey of Constant (Continuous) Monitors for Wrist Straps
ESD TR3.0-01: Alternate Techniques for Measuring Ionizer Offset Voltage and Discharge Time
ESD TR10.0-01: Measurement and ESD Control Issues for Automated Equipment Handling of ESD Sensitive Devices below 100 Volts
ESD TR4.0-01: Survey of Work surfaces and Grounding Mechanisms
ESD TR50.0-03: Voltage and Energy Susceptible Device Concepts, Including Latency Considerations
ESD TR3.0-02: Selection and Acceptance of Air Ionizers

Although there are many ESD documents available, only a handful of ESD documents that are required by a NEW ESD Coordinator to help him or her ESD in establishing the ESD Control program.
ANSI/ESD S1.1: Wrist strap
ANSI/ESD S4.1: Work surfaces – Resistance measurements
ANSI/ESD S6.1: Grounding
ANSI/ESD S8.1: ESD awareness symbols
ANSI/ESD S20.20: Standard for the development of an ESD control program
ANSI/ESD S541: Packaging materials for ESD sensitive items
ANSI/ESD S7.1: Floor material – Characterization of materials
ANSI/ESD STM2.1: ESD garments
ANSI/ESD STM3.1: Ionization
ANSI/ESD STM4.2: ESD Protective Work surfaces – Charge dissipation characteristics
ANSI/ESD STM9.1: Resistive characterization of footwear (exclude heel strap and toe Grounders)
ANSI/ESD STM11.11: Surface resistance measurement of static dissipative planar materials
ANSI/ESD STM11.12: Volume resistance measurement of static dissipative planar materials
ANSI/ESD STM 11.13: Two point resistance measurement
ANSI/ESD STM11.31: Evaluating the performance of electrostatic discharge shielding bags
ANSI/ESD STM12.1: Seating – Resistive characterization
ANSI/ESD STM13.1: Measuring electrical potential from electrical soldering/desoldering hand tools
ANSI/ESD STM97.1: Floor materials and footwear – Resistance measurement in combination with a person
ANSI/ESD STM97.2: Floor materials and footwear – Voltage measurement in combination with a person
ESD SP15.1: In use resistance testing of gloves and finger cots
ESD SP10.1: Automated handling equipment (AHE)
ESD TR 20.20: Handbook for the development of an ESD Control Program
ESD TR53: Compliance Verification of ESD Protective equipment and materials

An ESD Coordinator is encouraged to keep reading, evaluating and experimenting so as to improve his or knowledge. Keeping abreast with ESD technology that keeps changing is a must for the ESD Coordinator to ensure the ESD Control program is still functioning as requested over the years.

ANSI/ESD S20.20-2007 version has documented the need to have an ESD Coordinator in an ESD Control Program setup by any organization.
Regardless of the position being held by the individual, the person is commonly addressed as an ESD Coordinator by most organizations. Some organizations have position as ESD Control program manager. Whatever the organization calls it, the role of an ESD Coordinator and ESD Control program manager is alike, i.e. to verify the compliance of the program against ANSI/ESD S20.20 standard requirement.

Responsibilities of a typical ESD Coordinator include:
*Establish an ESD Control program
*Document the ESD Control program
*Verify the compliance and effectiveness of the ESD Control program against ANSI/ESD S20.20 standard
*Maintain the ESD Control program

Duties of a typical ESD Coordinator include:
*Setup a material qualification process
*Setup an equipment qualification process
*Setup an ESD Training material
*Train employees on ESD Awareness
*Investigate and rectify problems related to ESD
*Periodically audit the compliance of the ESD Control program
*Periodically enhance the knowledge on ESD subject
*Continually improve and enhance the ESD Control program

Authority of a typical ESD Coordinator includes:
Raise a Corrective Action Request when a non-conformance against the organization ESD documented requirement is seen

At times, the job of an ESD Coordinator can be very stressful due to many problems related to ESD. However the life of an ESD Coordinator can be much enlightened when the ESD Coordinator could find himself/herself a mentor.

It is highly recommended for an ESD Coordinator to find a mentor in his/her career life as an ESD Coordinator. Life with a mentor will be much lively and that is for sure.

It is common to find many documents or procedures in any established multinational organizations in every corner of the world. Documents or procedures spell out all the process requirements and specifications to run a process in the organizations.

The aim of the documents or procedures is to ensure the process is carried out in a control manner.

ESD Control program plan is just another document or procedure which is required to ensure ESD Control activities is done under controlled manner so that ESD sensitive items are protected from esd damage.

ESD Control Program plan shall address:
•The Compliance Verification Plan
•The Training Plan
•The Grounding/ Equipotential bonding system
•The Personnel Grounding
•ESD Protected area
•Equipments
•Handling
•Marking

Besides addressing both the ESD Administrative and ESD Technical elements, the ESD Control program plan also need to address:
•The most sensitive level of the ESD sensitive device being handled. When the most sensitive level of the ESDS device is not known, greater than or equal to 100V Human Body Model (HBM) damage is commonly taken as the most sensitive level of the device being handled by most organizations.
•The assignment of ESD Coordinator or ESD Control Program Manager who shall establish, document, implement, maintain and verify the effectiveness of the ESD Control program.
•Under certain applications where requirement is modified or deleted, the organization shall provide tailoring decisions, including the rationale and technical justifications based on the evaluation results done.

It is also important to remember that the ESD Control Program plan shall blend and integrate well with the internal quality system requirements to ensure its full effectiveness.

Distinguished ESD Consultancy who offer help in setting up the ESD Control Program are:
•Steve Halperin and Associates
•Bob Vermillion and RMV Technology Group

Here is a copy of ESD Control Program plan by Steve Halperin and Associates.

In today’s electronic industries, we can see many organizations are becoming more aware of the importance of having a proper esd control in their production lines to ensure their products are not damaged by electrostatic discharge.

One of the key areas that organizations need to look at is the Qualification process of the ESD materials and equipments.

It is at utmost importance to have the correct ESD materials and equipments used in the production lines to ensure the materials and equipments do not generate lots of static electricity which are harmful to the ESD sensitive parts.

To ensure the ESD materials and equipments are safe for production use, a Qualification process for materials and equipments must first be established. Secondly, correct and suitable ESD equipments must be purchased to help in performing the qualification of the materials and equipments.

The most important and basic esd equipment that would be needed in qualifying the ESD materials and equipment is the Surface resistance meter or Megohmmeter.

In the market places there are many brands and models of surface resistance meters that organizations can choose from. It is highly recommended choosing a surface resistance meter that can do the following measurements:
•Point to point resistance
•Resistance to ground
•Surface resistance and Surface resistivity
•Volume resistance
for both planar and irregular surfaces.

Some of the available surface resistance meter or Megohmmeter that can perform the above measurements in the market places are:
•Ohm-Stat RT1000 Megohmmeter from Static Solutions
•Monroe 272A Portable surface resistivity and resistance meter from Monroe
•Trek 152 Surface resistance meter from Trek

These models employed digital meter with setting at 10V/100V, two five pound electrodes, concentric ring electrode, and 2 point probe resistance meter as their accessories.

ESD measurements on the ESD materials and equipment must be carried out in compliance to ESD standard ANSI/ESD S20.20 and other supporting ESD standards listed in ANSI/ESD S20.20.

It is a common sight to see workers in electronic manufacturing industry wearing some kind of gloves or finger cots while working with the products.

Workers wear gloves or finger cots to protect the products from being damaged by contamination, finger prints or scratches from the wearer.

In most electronic manufacturing industries, ESD gloves and finger cots are widely used to provide ESD protection for the ESD sensitive parts that the companies produce.

There is a variety of ESD gloves and finger cots in the market place which are specially made for ESD protection purpose. Some of them include:

•ESD nitrile gloves , ESD vinyl gloves , ESD latex gloves, ESD conductive gloves
•Nitrile finger cots, pink ESD finger cots, Black Static dissipative finger cots

A good choice of ESD gloves or finger cots would be the one that meet your company process requirements. The company process requirements could require both ESD and clean room (contamination control) requirements or only ESD requirement depending on the type of ESD sensitive parts that the companies are producing.

A strenuous series of testing is required to check whether the ESD gloves or finger cots could induce contamination problems.

For ESD control application, a much simpler method can be used to check whether the ESD gloves or finger cots meet your ESD process control requirement.
For instance, when the workers are required to wear ESD gloves or finger cots before entering the controlled production area, then it is much easier to include and check the ESD gloves and finger cots as part of the system in the checking process.