ESD News Archives

Latex Gloves – Are You Allergic?


Many industrial manufacturing environments require workers to wear protective gloves, including during electronics and medical device production and assembly. Latex gloves not only protect workers from harmful chemicals but also protect products from worker contact and contamination during manufacturing Read more

ST 925 SMT Rework System–Three favorites combined into one nice savings


Save a few steps--and some money--with the Pace 925 SMT Rework System Pace has introduced a new low-cost “combination” system ideal for surface mount technology (SMT) rework. It’s worth adding up the savings by comparing the a la carte prices Read more

Metcal’s CV-5200 Connection Validation Soldering Station Changes Everything


You may or may not have heard about Metcal’s new soldering station, the CV-5200. The evolutionary tool removes much of the reliance on visual inspection of hand-soldered joints and adds a second, more technology-driven method for validating a successful Read more

Dry Air Static Control and Ionizers

Posted on by Andy in ESD News, Static Control Tips and Tricks Leave a comment

Dry air and ESD control

The specifications and devices being assembled determine the recommended humidity range for a manufacturing facility. When the air is dry, static control becomes much more challenging. Although ESD events may be reduced by increasing the humidity, unfortunately that same humidity may cause a reduction in the quality of moisture-sensitive devices because of corrosion, soldering defects and the popcorn effect.

Ionizer choices for reducing ESD

Although ionizers cannot replace grounding or shielding of ESD work surfaces, ionization can lessen ESD events in areas where dry air is normal.  Desco has number of ionization products available through All-Spec.

  1. Benchtop and overhead Ionizers – work surface ionizers create positively and negatively charged ions that are moved to the controlled area with fan-driven airflow.
  2. Point-of-use air ionizers – use compressed gas to combat electrostatic attraction neutralizing charges on particles causing contamination or visual defects on products.
  3. Laminar flow ionization bars – used with laminar flow hoods, controlled chambers and other contained applications.
  4. Room Ionization – reduces electrostatic discharge (ESD) and electrostatic attraction (ESA) in cleanroom environments.

For more information, consult the ESDA’s TR20.20-2008 RH information. Below find some of the significant statements about dry air and static electricity.

dry-air-popcorn-effectESD Handbook ESD TR20.20-2008 Section 2.3 Nature of Static Electricity:

  • Static electricity in the form of static cling and static shocks are more prevalent when the air is dry.
  • Heating interior air in the winter months dries out the already dry air in the higher latitudes.
  • Static charge accumulation is easier on dry materials since moisture on surfaces tends to allow charges to slowly dissipate or recombine.
  • Humidity control alone cannot provide static control since static charges are developed even at relative humidity levels of 90% and greater.
  • For most situations, 30 to 70% RH is considered the appropriate range.
  • Special areas, such as wafer fabrication, may require lower humidity control for processes that are affected by moisture (e.g., photoresist application).
  • Soldering is known to be affected by high relative humidity conditions (>70%).
  • Ionization is an important consideration in areas with low ambient humidity to aid in reducing charge accumulation levels and provide neutralization of charges after they are developed but before they can cause difficulties.

 

desco-point-of-use-air-ionizerESD Handbook ESD TR20.20-2008 Section 5.3.16 Humidity:

  • Humidity is beneficial in all ESD control program plans.
  • Contact and separation of dry materials generates greater electrostatic charges than moist materials because moisture provides conductivity that helps to dissipate charge.
  • ESD effects are most noticeable in the winter since heating systems reduce building environment moisture.
  • Geographic location (desert vs. coastland) is a major contributor to ambient conditions inside buildings.
  • Any circumstance that results in a low relative humidity will permit a greater accumulation of electrostatic charges.
  • Relative humidity above 30% in ESD protective areas is desirable as long as other adverse conditions are not created as a result of humidity levels.
  • In general, an upper limit of 70% is desirable to prevent corrosive effects on the metal portions of electronic devices and assemblies.
  • Dry air increases the tendency to generate electrostatic charges on dry materials and performance of many ESD protective materials degrade.
  • When exposed to low humidity conditions, some ESD protective materials become totally ineffective or become sources of electrostatic charges.
  • Evaluation of ESD control materials should include performance testing in controlled environments at the lowest expected operating relative humidity level.
  • Manufacturers of ESD protective materials should be able to provide performance data in regards to relative humidity.
  • Materials should be tested in moderate humidity conditions as well to ensure they do not become “too conductive” and present a potential safety hazard to personnel working with substantial voltages. See the Personnel Safety section of this handbook for further guidance in this area.

 

Humidity control alternatives

 Humidity control in factories or physically large areas or buildings can be difficult and expensive. In smaller rooms or areas, it may be possible to use portable humidifiers to raise the immediate area humidity. However, in many large facilities and factories the environmental systems need to include steam generation and monitoring equipment to control humidity. This type of equipment is expensive to install and purchase especially in pre-existing facilities. To reduce the total cost impact, companies should consider the need for humidification equipment when planning new facility construction.


ESD Mat Cleaning Dos and Don’ts

Posted on by Andy in ESD Mats, ESD Testing Leave a comment

How you clean your ESD mat–and with what–can make a big difference in performance and in life expectancy of the product. Excellent cleaning solutions have been specifically formulated to easily and effectively remove flux, solder, chemicals, dirt and grime without damaging your mat. Using these special cleaning products will help extend the life of your mat.

Follow these dos and don’ts when cleaning your ESD mat – 

itw-chemtronics-9700_es1664t_dv_webxlDon’t

  • Clean with alcohol or ammonia. These chemical will cause your mat to dry out and become brittle.
  • Clean with a silicone-based cleaner. It will leave a residue that could reduce the mat’s ESD capabilities.
  • Use strong chemicals. They could corrode your mat.

Do

  • Clean with the proper solution and mixture for your specific mat.
  • Create a cleaning schedule so you’ll never have to worry about residue build-up.
  • Consider the brand of the cleaner. Oftentimes companies test their cleaners on their mats.
  • Remove any residue immediately, such as flux and solder.
  • Test your mats regularly to ensure optimum performance of your ESD mat.
  • Clean your mat if the RTT or RTG tests show a rating less than normal.

 

All-Spec carries a selection of mild and highly effective ESD mat-cleaning solutions.


What to Consider When Choosing an Electro-Static Disapative (ESD) Mat

Posted on by Andy in ESD Mats, ESD News Leave a comment

Choose your ESD mat with care

sierra-1695_ftwg_dv_webxl

Sierra Heavy Duty Rubber Worktop Mat Kit with Wrist Strap, Ground Cord and Snaps

Like everything in manufacturing, the Electro-Static Disapative (ESD) mat, whatever type, continues to evolve to keep areas ESD-safe. Before you buy, think about what you really need to do the job. Mats come in all sizes and shapes and materials and can be expensive, depending on the application.

First the skinny on ESD mat types –

Conductive Mats (101 to 105 ohm) – low electrical resistance allowing ESD to flow across the surface. When grounded the ESD flows to ground and neutralizes the excess charge on the mat and worker.

Anti-Static Mats (105 to 1012 ohm) – higher electrical resistance than conductive mats and like conductive mats allow ESD to flow across the surface, however at a slower rate to prevent damage to microcircuit devices unable to tolerate a sudden flow of static charge from the device to a grounded mat.

Non-Conductive Mats (Insulator) (1012 ohm or higher) – prevent the flow of ESD across the surface. Generally used in high voltage environments where electrical charge movement of is undesirable and potentially life threatening.

 

CONSIDERATIONS –

  1. Rate of Neutralization– for work environments and many applications mats for neutralizing ESD range from 105 to 1011 ohm to efficiently address static. Dissipation of static electric charges will happen rapidly and at a controlled rate.
  2. Setting– Will the mat be used on carpet or hard surface like concrete? Mats can cause accidents, for instance, tripping if on carpet, or sliding if on concrete. Most rubber and vinyl conductive and anti-static mats will not wear well against chairs or carts. The wheels and weight will cause breakdown. Use ESD mats made to work on carpet or under chairs.
  3. CostA highpriced mat doesn’t mean it’s the right mat. For instance, more expensive ones like conductive mats could damage devices with microcircuits by reducing static charges too fast.
  4. Cleaning – Keep your mat clean and residue-free. Special static control cleaning solutions are available. Some mats can be dry-mopped or just swept.
  5. Life of Your Mat – If properly cared for, mats can last for years. Depending on your mat type, they can be self-healing and also very resistant to solder drips and spits.

Benefits

  • ESD mats protect sensitive equipment by drawing static electricity off workers before they touch susceptible objects. An ESD mat safely transfers static from a worker to the ground.
  • They’re generally cushy—so they help your back, your feet, everything that can begin to hurt after hours of standing up. Think anti-fatigue.

Note – Ungrounded conductive or anti-static mats hold an ESD charge and will transfer a charge to the next thing the mat touches.

All-Spec carries a large assortment of ESD mats. Have questions? Our customer service representatives can help guide you to the right mat for your application.

 

Did you know?  The most significant invention to accelerate the electronics revolution happened in 1948 with the invention of the transistor. Next, in 1958 Jack Kirby invented the integrated circuit (Nobel Prize winner 2000) Half a year later Robert Noyce (and a co-founder of Intel) opened the door to smaller and more reliable, complex devices with the invention of the computer chip. Today, IC architectures can carry more than a billion transistors on a chip and soon may execute more than 4 trillion calculations per second. All this has led to less spacing between pin-outs of each chip and the transistors’ gates and junctions and, therefore the need for advanced ESD control. (more)


The Benefits of ESD-Safe Turntables -Take One for a Spin

Posted on by Andy in Cleanroom, ESD News, Product Reviews, Static Control Tips and Tricks, Technical Articles Leave a comment

Remember the lazy Susan?

imagesOnce a staple on every dining room table where with a spin of a wooden disc your salt and pepper shakers suddenly appeared in front of you. The same idea works for an ESD-safe turntable, however this disc does much more than turn.

Just like the revolving server, the turntable rotates to make working on large products and assemblies easier. With an ESD-safe turntable you avoid lifting heavy objects and–potential back injuries. With just a turn of the wheel you can access your next work area with ease—no lifting, lugging or jostling into place. And of course, the turntable eliminates electrostatic build-up.

The devices can be used on grounded or ungrounded surfaces, however on ungrounded surfaces the turntable must be grounded. The sizes range from 12” to 20” and come in different shapes depending on your application and preference.

esd-turntable

ESD-Safe Turntable – Not for use with food. Great for heavy objects.

The ESD-safe turntable can be an invaluable tool in the electronics industry and has become a staple in its own right at many workstations. See a choice of ESD-safe turntables at All-Spec including these brands – Protektive Pak, Fancort, Sovella and Desco.

Summary –

  • Keeps heavy objects grounded and shielded from static
  • Eliminates heavy lifting or transport
  • Protects workers, products and components
  • Useful all kinds of heavy assembly, rework or maintenance jobs
  • Removes charges on contact with grounded ESD surfaces

 

 

SEE HOW IT WORKS – Protektive Pak ESD Turntable


Industry Council Wants Universal Understanding of Electrical Overstress

Posted on by Andy in ESD News, Industry News Leave a comment

 Electrical Overstress (EOS)

In August 2016, the Industry Council on ESD Target Levels released a new white paper on Electrical Overstress (EOS). The Council gathered information via a survey sent to more than 90 companies asking them about the importance of EOS to their business and their methods for addressing EOS issues. One of their first steps—create a universal definition of EOS –

EOS – an electrical device suffers an electrical overstress event when a maximum limit for either the voltage across, the current through, or power dissipated in the device is exceeded and causes immediate damage or malfunction, or latent damage resulting in an unpredictable reduction of its lifetime.

In general, they found that ESD damage was often confused with EOS damage and those responsible for identifying failures were many times either inconsistent or incorrect in their findings. The Council also created multiple goals after gaining insight from the survey and laid out plans for the future.

Industry Council goals –

  • unified agreement eosReduce EOS occurrences
  • Create a unified global understanding of what constitutes EOS
  • Understand how EOS damage signatures can result from a wide variety of root causes
  • Address possible preventable failures showing EOS damage
  • Explain the non-correlation between EOS return rates and component ESD target levels
  • Standardize EOS reporting to reduce mislabeling damage as EOS
  • Continue to dispel the notion that EOS can be avoided by making devices more ESD robust (ref. JEDEC publications JEP155 [1] and JEP157)

 

The white paper contains very detailed explanations and diagrams to help EOS data reporters improve. (IC suppliers, i.e., customers, applications engineers and system builders). One of their most significant findings concerned Absolute Maximum Rating (AMR) and the actual meaning of maximum limit. (see definition of EOS) and the different methods a manufacturer uses to determine a device’s AMR values.

Industry Council on ESD survey resultsThe survey concluded –

  • Some suppliers do not include ESD limits as part of their AMR because testing to establish the ESD limits often does not have the similar statistical data required for setting more traditional items such as voltage.
  • Some suppliers do place ESD limits in their AMR definition believing this is part of the overall agreement that must be met between supplier and customer.
  • Other suppliers placed ESD limits in AMR sections because it was the only place that made sense to them.

 

The Council asks manufacturers to go back to suppliers to verify the AMR information published before the release of their EOS white paper.

 The white paper concluded –

  1. EOS has never been fully understood or accurately and thoroughly explained or interpreted.
  2. Meeting ESD levels beyond the specification targets does not mean a reduced rate of EOS returns. Overwhelming data from the Industry Council supports this assertion.
  3. Industry-wide surveys indicate a) EOS is the most common attribute of reported returns, b) most respondents indicated they use “damage signature” to determine EOS.
  4. EOS almost always represents permanent damage.
  5. Most common cause for EOS – 1) misapplication, 2) violations to absolute maximum ratings, 3) exposure to electrical stress events during assembly and in the field that violate the AMR
  6. Establishing a universal definition of EOS should foster better communication in the industry when addressing EOS problems
  7. Absolute maximum rating requires a more in-depth definition informing customers that exceeding the AMR value has risks and can lead to irrecoverable device damage. Also, an EOS event occurs if any AMR is exceeded for any period of time.
  8. AMR specifications must include constraints for excursions in system operation and environmental conditions needing to be accommodated by system design to allow safe operation and handling of semiconductor components.
  9. Electrical and environmental conditions for intended AMR values must be documented in datasheets.
  10. In unique systems requirements, the AMR values must be provided by semiconductor component suppliers according to electrical and environmental conditions given by system manufacturers.

The Industry Council hopes to foster understanding of EOS, the root cause determination for resolving EOS issues and implementation of methods for EOS mitigation.

 

 


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