ESD products are going through a phase of major upgradation to meet the emerging needs of the industry
Clean room and electrostatic discharge control products are a must for any electronics manufacturing unit as electrostatic discharge (ESD) is harmful for electronic components and products. Static control products are used throughout the electronics, defence, fibre optics, telecommunications, medical, disk drive and automotive industries for the protection of sensitive electronic components and products, both inside and outside the electrostatic discharge protected area (EPA).
According to industry analyst NanoMarkets, the demand for ESD products continues to grow across the globe, and the popularity of pervasive computing and electronics is expected to increase the size of the market for ESD products. Also, the growing use of nanomaterials will continue to give an impetus to the ESD products market.
With electronics manufacturing on the rise in India and with the growing international demand for Indian electronics, the ESD products market in India is experiencing an upsurge. To keep pace with the international market trends, ESD products in India are also going through a phase of major upgradation.
What’s new in the market
ESD products are used for protecting electronic circuit boards and other electronic products from electrostatic charges. From the array of ESD products in the market, let us explore the new products in antistatic flooring and tabletop systems, ESD test and measurement devices, static elimination products and ESD safe adhesives and tapes.
Companies continue to develop and create new ESD measurement technology as per the needs of the industry.
New types of wrist strap cum dual footwear testers are in the market, which are used for testing the validity of the ESD wrist strap and footwear. These instruments independently and simultaneously tests the right and left feet as well as the wrist strap, thereby reducing the testing time by half. It offers the operator a visual and audible ‘pass’ or ‘fail’ verdict for both feet and the wrist strap before entering the EPA.
Zeebeetronics has launched a ‘talking’ wrist strap and footwear tester—the Z1033, which the company claims is the first of its kind in the market. “This talking instrument gives an audible message of the condition of the ESD wrist strap and footwear in use. It has a pass range of 0.75 to 10.0 meg ohm for the wrist strap, and 0.75 to 35.0 meg ohm for the footwear. The tester works on a 9 V DC battery and is a lightweight device of 200 gm,” informs Zarir Bharucha, proprietor, Zeebeetronics.
Recently, Sumitron Exports Pvt Ltd has also introduced a wrist strap and heel grounder combo tester from ACL Inc, a US based company. “ACL 750 records the actual resistance of wrist straps and heel grounders from 100 kilohms to 100 megohms, with an option to go up to 1000 megohms. It also generates reports like its entire log, a daily log, ESD certiﬁcation expiration, etc, for emailing and printing,” explains SK Jain, managing director, Sumitron Exports Pvt Ltd.
The latest offering from IDB Systems is a portable wrist strap tester—the ID-471P. Launched in April 2012, the pocket sized ID-471P is easy to carry and weighs less than 180 gm along with the battery. The tester draws power from the battery only while the test is being performed, thus maximising the battery life, and a simple switch provides a self-test function to ensure the unit is working within specifications.
Handheld particle counter: The new Aerotrak handheld particle counter, Model 9303, offered by Sumitron Exports features a sturdy yet lightweight high impact injection moulded plastic design for easy handling. The instrument is easy to configure using an intuitive keypad. The internal memory can store up to 1500 sample records of particle count data, which can be conveniently viewed on screen or downloaded using a USB port. This instrument reports up to three particle sizes simultaneously.
ESD and its impact
An electrostatic discharge (ESD) occurs when electricity accumulates and cannot flow, and this is caused by the movement of people and materials in an environment. When this charge is transferred from the material that carries it to an electrostatic sensitive device, typically a metallic object, it is discharged in the form of a spark. This ESD shock can occur in varying degrees, and is harmful to electronics components and devices. Therefore, a clean room environment is mandatory for companies in the electronics industry. A clean room is one in which the concentration of airborne particles generated by people, processes, facilities and equipment is controlled to specified limits. The level to which these particles need to be removed depends upon the standards required. The most frequently used standard is the Federal Standard 209E, which establishes standard classes of air cleanliness for airborne particulate levels in clean rooms and clean zones.
Electrostatic voltmeter: The 341B electrostatic voltmeter has been introduced by Cir-Q-Tech Tako Technologies. This instrument, with an extremely high accuracy and resolution and is used for measuring static charges in specialised research applications. “It can measure static charges between 0 to 20 KV with an accuracy of +-0.5 per cent. As a contrast, the typical field meters in the market have an accuracy of +-5 per cent of the full scale,” says KV Keshavamurthy, managing director, Cir-Q-Tech Tako Technologies. This instrument is a DC stable, precision electrostatic voltmeter for making non-contacting surface voltage measurements. The 341B employs a field nulling technique that achieves DC stability and high accuracy even if the probe to surface spacing changes. This permits measurements of either stationary or moving surfaces without the need to establish fixed spacing to maintain accuracy.
The LED static charge meter, recently launched by Zeebeetronics, is a non-contact, static locating and measuring instrument. It utilises a 10 LED bar graph display to indicate the magnitude and polarity of the electrostatic charge. It has a very fast response time compared to analogue and digital static meters and is also far more rugged since it has no delicate LCD display or analogue meter. Its extremely fast response time makes it a unique offering in the market, claims the company.
ESD safe work surfaces
It is necessary to make the surface and other work areas antistatic in an electronic manufacturing or assembling facility.
Antistatic mats are made of polyethylene film and are used to trap impurities in areas that require dust and dirt control. The surface pulls dirt and dust off shoe soles before they can contaminate a clean room.
Earlier this year, 3M introduced clean walk mats for clean rooms. Shares Ashutosh Shirodkar, general manager, industrial adhesives and tapes division, 3M, “The product has unique removable sheets that can be peeled back to expose the adhesive surface that holds dirt securely. Adhesive mats hold dirt securely, protect and preserve the floor and carpeted surfaces.” These mats are available in both framed and unframed versions.
Innotech’s clean room sticky mats, introduced in April 2012, have 30 layers of thin but tough polyethylene film coated with a medium tack adhesive, which removes dirt and other bacteria carrying particles from boots, casters, and cart wheels. These adhesive tacky mats are not damaged by shoes, boots, or cart wheels and are available with an adhesive backing in order to be secured directly to the floor. In areas where the adhesive backing is not ideal (such as a carpet), the company offers aluminium sticky mat frames to secure the mats.
The latest ESD laminates launched by Cir-Q-Tech Tako Technologies come with a natural wood finish, unlike the commonly available laminates in the market, which are either grey or white because of the chemicals added to create a static dissipative character. Says
KV Keshavamurthy, “We have now perfected the process of creating a laminate that has the pleasing aesthetics of natural wood along with being ESD safe. We are so confident of the performance of this product that we offer a lifetime guarantee on the ESD properties of the laminate.”
Static elimination products
ESD ionisers neutralise a static charge via balancing the ions between the molecules in the gasses of the surrounding air. These are typically used to control static on isolated conductors that cannot be grounded and insulative objects (like standard plastics). A recent innovation in the ionisers is the introduction of hybrid digital control AC technology developed by Shishido Electrostatic Ltd, Japan. This is offered by Advance Tech Services Pvt Ltd. With this technology, the ionisers achieve high voltage output from small and light weight transformer, a longer emitter life, less particle attraction by emitter, low maintenance and best performance even in conditions where there is low maintenance of the emitter. The model BF-4MA, is a slim and light weight air ioniser with HDC-AC for covering wide area around 400 mm.
Another new technology introduced recently in static eliminators (ioniser) by Zeebeetronics is the use of ‘shockless bars’. This static eliminator works on the principle of high voltage corona discharge, to produce the neutralising ions. The static eliminator system is designed to neutralise the charges by the ‘ion showering’ process wherein the surface charges present are neutralised. It is designed for continuous use and the ‘shockless bars’ ensure total safety even if the electrodes are accidently touched.
Awareness of international ESD standards
There are different standards that cover the specific requirements of a clean room manufacturing system. These include standards for specific products or procedures such as packaging requirements and grounding. The typical standards in this group are ANSI/ESD S6.1 Grounding and ANSI/ESD S541–Packaging Materials for ESD sensitive items. There are also specific test methods standards that focus on ESD in the electronics environment. These include standards such as ANSI/ESDA-JEDEC JS-001-2010—Device Testing, Human Body Model and ANSI/ESD STM7.1: Floor Materials—Resistive Characterisation of Materials, to cite a few.
According to KV Keshavamurthy, customers must be aware of international ESD standards so that they select only those products that meet those standards. “We offer training or testing as per these standards so that customers can be sure of buying the correct products,” he says.
ESD safe adhesives and tapes
ESD safe adhesives and tapes are used in ESD sensitive environments for sealing antistatic bags; for packing of electronic components, medical instruments, precision mechanical equipment, and for splicing of films.
The most recent innovation in elastomeric adhesive sealants is the introduction of MS polymer based sealants by 3M in April 2012. Called the 3M 740 and 3M 760 series, they have no isocyanates or solvents, a feature that is essential for any application where environmental health and safety (EHS) are critical. These sealants and adhesives stand out from other similar products available in the market on account of a very low content of volatile organic compounds (VOC). Informs Ashutosh Shirodkar, “3M 740 and 3M 760 have a very low VOC formulation, which is paintable even when wet. Its faster skin time, excellent UV resistance and a broader adhesion capability, along with a variety of substrates without the need of primer make this product unique amongst the conventional available products.”
The recently launched double coated tapes by Polyonics are ideal for bonding materials that will be exposed to extremely high temperatures and harsh manufacturing environments. The ESD versions (XT-652 and XT-653) are ideal for bonding static sensitive devices (SSD) to a wide variety of substrates. The tapes provide low peel voltage (<100 v) when the liners are removed, and again when the bonded part is removed, specifically helping to eliminate electrostatic charges.
How to choose ESD products
According to SK Jain, one should choose ESD products according to the class of the clean room being set up. A clean room can be set up under different classes such as Class 1, Class 10, Class 100, Class 1000 and Class 100,000, depending upon factors like air changes per hour, which is ascertained by the ceiling coverage of the room; and the percentage of high efficiency particulate air (HEPA) present in the room for which HEPA filter is required, which is a type of filter that can trap a large amount of very small particles, etc.
Also, while there is a huge array of ESD products, these should be selected after proper consultation with experts. For instance, while buying ionisers, one should look for reliability of the make, ozone produced in product and how long it can maintain the balance of ion. Shares Anil Gupta, managing director, Advance Tech Services Pvt Ltd, “Most customers are not aware of the fact that ionisation is a very important part of ESD precautions. At Advance Tech, we offer ionisers which can maintain balance of ion for three years and some technologies which can work for 5-10 years even in no maintenance conditions.”
By Nitasha Chawla