Production of RFID Inlays: The Process Must be Perfect
By Florian Hierl, Business Development Manager RFID, Delo Industrial Adhesives
In 2007, RFID — the keyword and hope of many users, particularly in supply chain management and logistics processes — took a short break in development for technological and also systematic reasons. Basically, technological challenges (e. g. in the field of UHF) had to be clarified. And, due to a general and worldwide broadening of RFID applications, the value proposition RFID means for production, logistics and anti-counterfeiting could be made clear to a wide spectrum of users. The horizontal expansion to a wide range of users and the knowledge gained on the realization of RFID technology are the signs for a sustainable enhancement in the near future.

In the value chain, Delo Industrial Adhesives contributes to meeting the requirements regarding productivity in the RFID inlay production as well as product quality of the inlays in the application (see Illustration to the right). The adhesives Delo has developed for contacting the chip to the antenna substrate play a major role for the efficiency of HF and UHF inlays.

In order to explain the adhesive's tasks more clearly, a reel-to-reel production process of RFID inlays is exemplarily illustrated to the right.

The antenna produced in a preprocess is fed to the production machine from a roll. The antennas are mostly made of PET basic laminates, either with copper or aluminium metallization. Moreover, antennas printed with silver inks are available. Paper- or polyimide-based antennas are common substrate variants.

Production in Cycles Tuned to Seconds
The first step of the inlay production is the adhesive application to the contact surface of the antenna, to which the chip is to be attached later. The adhesive is either applied through needle dispensing, or by means of screen printing, as shown in illustration 2, in the case of parallel antennas on the substrate, that is to say larger web widths. Afterward, the chip is placed from the wafer to the antenna into the adhesive with the flip-chip method. This procedure is applied as the active side of the chip with the bumps (contacting areas) is open and directs upward after chip production, and functionality is only achieved if this side faces the antenna so that the chip must be “flipped.”

The placement of the chip is followed by a buffer station in order to subsequently cure the adhesive in a thermode station (see photo to the left). In doing so, the temperature is added to the system with an upper and a lower heated plunger (thermode). Beside heat addition, the thermodes fulfill the function of pressing the chip to the antenna under defined force, ensuring electrical contacting. Afterward, one inspection step (functionality test) is interposed in order to detect possibly missing components and make them recognizable for the following processes (e. g. conversion to a label).

In principle, the adhesive — either a non-conductive die attach adhesive or an anisotropic conductive (in one spatial direction) product — undertakes the task of reliably fixing the microchip to the antenna at a defined position. In addition to purely mechanical tasks, the adhesive ensures electrical contacting.

In case of chips with stud or Pd bumps (as shown in photo to the right), electrical contacting is only indirectly reached by the adhesive. These bump variants are distinguished by a very sharp-edged geometry and inhomogeneous surfaces so that the bumps directly penetrate the metallization layer when placing the chip onto the antenna substrate, closing the electrical contact. The adhesive in the form of a non-conductive product (NCP = Non Conductive Paste) only ensures the chip’s position accuracy in all three spatial directions in this case. Even minimal lifting of the chip from the substrate opens the contact and would lead to a functional deficiency of the inlay.

This is a schematic illustration of contacting with stud bumps (yellow). The adhesive (blue) ensures exact positioning of the chip.

Beside mechanical fixing and positioning, the second adhesive type, the so-called ACP (Anistropic Conductive Paste) directly ensures electrical contacting through a polymer resin matrix filled with special particles. ACPs are mainly used if the chip is equipped with geometrically very homogeneous and flat Au or NiAu bumps (as shown in illustration below) which cannot penetrate the metallization layer of the antenna. Naturally, these adhesives must meet the same performance requirements like the NCP and must not allow any relative movements in any spatial direction of the chip to the antenna.

Schematic illustration of a flat gold bump (yellow). It is contacted by means of an anisotropic adhesive (blue) filled with conductive particles (silver).

Cost Optimization through New Adhesives
In the meantime, Delo provides three generations of adhesives which meet high reliability requirements and reach extremely fast curing speeds at low temperatures at the same time. Thus, the adhesives can be cured with standard production equipment at a thermode temperature of 140°C in 5 seconds, whereas previous standard thermode temperatures could reach up to 210°C and cycle times of approximately 10 s were the rule. Delo’s highly accelerated adhesives can increase the productivity of standard systems to approx. 25,000 pieces per hour. Moreover, their low curing temperatures make it possible to use substrates which are less heat-stabilized and, therefore, less expensive.

Both advantages save costs in the inlay production process. Delo makes an active contribution to cost optimization in this price-sensitive business line. The adhesive groups are complemented by miscellaneous variants of particles and particle mixtures so that an optimized solution can be provided for nearly any combination of antenna, chip, process requirements and reliability needs.

Florian Hierl joined Delo in October 2001. In April 2006, Florian took over the responsibility for the business development in the field of RFID with focus on flip-chip and strap-attach. With his expertise in this field, Florian’s function is to extract the gained knowledge of market and technology into the company’s core strategy for future business in smart label and in flip-chip applications.

Florian graduated in Chemical Engineering in 1998 and worked 3.5 years in Research to apply suprcritical fluids in chemical reactions. Prior to his employment in Business Development he was sales manager for Delo in Germany.

Delo Industrial Adhesives has nearly 45 years of experience in the field of industrial adhesives. Delo has been working in the smart card sector with several proven records of success: The Delo products for the flip-chip industry enable secure electrical contacting and very short production times; opaque chip encapsulation compounds protect the chip against unauthorized viewing and copying; the Dam&Fill method patented by Delo enables defined geometries as well as minimum encapsulation heights.

Singapore Research Produces Protection from Moisture and Oxygen
A team of scientists from Singapore’s Institute of Materials Research and Engineering (IMRE) has developed a new patented film that has the highest reported water vapor barrier performance to date, as tested by the UK Center for Process Innovation. The tests have shown that the new film is 1,000 times more impervious to moisture than existing technologies. This means a longer lifetime for plastic electronic devices such as solar cells and flexible displays that use these high-end films but whose sensitive organic materials are easily degraded by water vapor and oxygen. The new technology is a boon to the burgeoning plastic electronics industry that aims to deliver flexible, lightweight and cheap electronics products to consumers in ways that silicon electronics may never reach such as disposable or wraparound displays, cheap identification tags, low cost solar cells and chemical and pressure sensitive sensors.

A research institute of the Singapore’s Agency of Science, Technology and Research (A*STAR), IMRE’s breakthrough technology comes as Singapore seeks to jumpstart a plastic electronics industry locally as part of the country’s long-term plan to anchor new knowledge-intensive industries in the economy. The global plastic electronics industry is projected to grow to a market size of more than $23 billion in the next 5 years.

The performance of devices like organic light emitting diodes (OLEDs) and solar cells is sensitive to moisture because water and oxygen molecules seep past the protective plastic layer over time and degrades the organic materials which form the core of these products. Current commercially available films used to protect these materials have a barrier property or water vapor transmission rate of about 10-3g/m2 per day, or one thousandth of a gram per square meter per day at 25°C and 90 percent relative humidity (RH). However, the ideal film for organic devices would require a barrier property of better than 10-6g/m2/day at 39°C and 90 percent RH, or one millionth of a gram per square meter per day.

Defects such as pinholes, cracks and grain boundaries are common in thin oxide barrier films when fabricated onto plastic substrates. These defects cause a pore effect, where oxygen and water molecules are able to seep through and penetrate the plastic barrier. Current barrier technologies focus on reducing these defects by using alternate organic and inorganic multi-layers coated on plastic. These multiple layers “stagger” corresponding pores in adjacent layers and create a tortuous, lengthy pathway for water and oxygen molecules, making it more difficult to travel through the plastic.

In contrast, IMRE has taken an innovative approach to resolve the ‘pore effect’ by literally plugging the defects in the barrier oxide films using nanoparticles. This reduces the number of barrier layers needed in the construction of the barrier film down to two layers in this unique nanoengineered barrier stack. IMRE’s barrier stack consists of barrier oxide layers and nanoparticulate sealing layers. The nanoparticles used in the barrier film have a dual function, not only sealing the defects but also actively reacting with and retaining moisture and oxygen.

The result is a breakthrough moisture barrier performance of better than 10-6g/m2/day, or one millionth of a gram per square meter per day, which surpasses the requirements for flexible organic device substrates. The barrier film also has a lag time of more than 2,300 hours at 60°C and 90 percent RH (i.e. the time required for moisture to pass through the barrier film under those conditions). These plastic barrier properties were tested and validated by the Centre for Process Innovation, UK.

“With a level of protection that surpasses the ideal requirements for such films to date, manufacturers now have the opportunity to extend the lifetime of plastic electronic devices by leaps and bounds,” said Senthil Ramadas, principal investigator of the project.

A stumbling block in developing ultra-high barrier substrates has been the availability of an appropriate testing methodology. Overcoming this hurdle, the IMRE project team has developed a highly sensitive moisture and oxygen permeation measurement system in tandem with the development of the film that is able to effectively measure permeation of less than 10-8g/m2/day. This system has been successfully implemented in a number of service based industry projects.

Recognizing the potential of the high performance substrate technology, Exploit Technologies Pte Ltd (ETPL), the commercialization arm of A*STAR, has funded the team through a flagship project that seeks out research with commercialization potential.

IMRE has already signed agreements with a number of companies to advance the technology into the commercial domain. This includes a collaboration agreement with G24Innovations, a thin film solar cell manufacturer to look into developing the films for use in solar cells.

DuPont and Dainippon Screen to Develop Printed OLED Technology for Growing Flat Panel Displays Market
DuPont and Dainippon Screen Manufacturing Co., Ltd., have announced their intention to form a strategic alliance to develop integrated manufacturing equipment for printed organic light emitting diode (OLED) displays. The companies also have signed an agreement relating to their intention to bring together the elements needed – materials, technology and equipment – to mass produce OLED displays, delivering higher performance at a lower cost.

"The flat panel display market is about $100 billion annually and growing. DuPont is applying its science to make possible more vivid displays that are lower cost than current LCD displays,” said David B. Miller, group vice president, DuPont Electronic & Communication Technologies. “We are excited to combine our strengths with Dainippon Screen’s unique printing technology to bring to market the core technology that will enable improved high definition televisions and other flat panel displays."

The companies are developing integrated coating and printing equipment for the fabrication of OLED displays from solution, an approach that is unique in the industry and can significantly reduce manufacturing costs for OLED displays. DuPont brings to the alliance its distinctive small molecule-based OLED solution materials and proprietary process technology from which excellent performance has been obtained in testing. Dainippon Screen has developed a unique printing technology, called nozzle printing, in which the OLED materials can be printed accurately at very high speed. The goal of the alliance is to develop integrated OLED printing and coating equipment that will significantly reduce the production costs of flat panel displays, with the aim of extending OLED technology to large size displays and making them cost-competitive with LCDs.
The companies have been working together over the past three years to jointly develop nozzle printers as an efficient method for printing OLED displays from solution. The first production scale printer is currently being constructed.

NanoMarkets Issues New Report on Organic Photovoltaic Markets
NanoMarkets, an industry analyst firm, has issued a new report that examines the market potential for solar cells using organic materials or a hybrid organic/inorganic dye sensitive cell (DSC) approach.  According to NanoMarkets, the organic photovoltaics market will generate nearly $1 billion in revenues by 2015.  The report notes that 2008 will be the first year that organic PV products will be available commercially and that progress in the organic PV sector is being made possible by the substantial venture capital and strategic investments that have been made in this sector in recent years.   

Other key findings from the report include the following:

• Organic approaches to PV are now being taken seriously as a low-cost solution for mainstream solar panel and building integrated photovoltaics (BIPV) applications. In the US, this effort is getting federal government backing from the Solar America initiative. Meanwhile, the demand for BIPV systems is expanding because of their lower energy usage and reduced overall carbon footprint; especially in the UK and Europe where zero energy buildings are required by legislation. NanoMarkets projects that BIPV will account for $470 million in revenues for the organic PV sector by 2015.

•  While the conversion efficiencies of commercial PV based on organic materials cannot yet match inorganic approaches (thin film for example), organic solar cells win out on low cost. DSCs are already the lowest cost of all printed PV cells types and “pure” organic approaches to PV promise even more radical price improvements. All this makes organic PV highly attractive for cost sensitive markets such mobile electronics and residential applications. 
  
  
• Recent advances in materials and cell architectures for organic PV have also led to improved efficiencies that will propel organic PV further in the marketplace.   The addition of fullerenes to more conventional organic PV materials is a move that will help to double the efficiency of organic based cells in the next couple of years. Novel dyes for DSC are leading to 11 percent efficiencies in the lab.  Meanwhile, progress is being made in the development of bulk heterojunction architectures.  

Universal Display Corp. Delivers Flexible OLED Prototype with New Capabilities to US Army
Universal Display Corp., a company focused on displays and lighting products through its PHOLED phosphorescent OLED technology, has developed and delivered a novel OLED display prototype to the US Army. The prototype demonstrates a flexible OLED display that incorporates both visible green emission for daytime operation and infrared (IR) emission for use in dark environments.

Developed through a two-phase Small Business Innovation Research (SBIR) program with the US Army, this initial prototype was designed to demonstrate capabilities that would enable soldiers in the field to view one display in two modes. Using Universal Display’s high-efficiency PHOLED technology, the OLED display prototype provides green-color emission for daytime operation and can be switched to operate in an IR-emission mode, which can only be detected through specialized night-vision goggles, for covert operations. By integrating this onto a flexible substrate, the company has achieved a design suitable for portable, rugged and conformable use both day and night in the field.

As part of an ongoing effort by the US Army to develop next-generation applications that will enhance field operations for US soldiers, the prototype was delivered to Mr. Raymond Schulze, chief, Battle Command Interface Branch of the US Army Communication Electronics Research and Development Engineering Center (CERDEC). This project complements flexible display development ongoing at the US Army’s Flexible Display Center at Arizona State University, of which Universal Display is a founding member. With further technology development, this display concept may lead to the realization of important, new display functionality that can enhance the communications capabilities of the soldier.

“The design and delivery of this display prototype marks another milestone for our high-efficiency, phosphorescent OLED technology and our work with the US government,” said Steven V. Abramson, president and chief executive officer of Universal Display Corp. “The prototype provides further evidence of the benefits that our PHOLED technology can provide in a variety of environments and applications for the military and commercial sectors.”

The active-matrix OLED prototype display, based on Universal Display’s proprietary PHOLED technology, employs proprietary visible-emission PHOLED materials as well as new IR-emitting PHOLED materials and device structures from the Universal Display team in conjunction with its partners at the University of Southern California and the University of Michigan. In addition, this 100 dpi prototype was built on flexible metal foil using low-temperature, poly-silicon backplane technology from Palo Alto Research Center (PARC), and was integrated into a system for the Army by L-3 Communications Display Systems, a division of L-3 Communications Corporation.

Nanoident Partners with Life Science and Technology Leaders to Detect Airborne Pathogens for European Defense Agency
Printed Sensors a Key Component of Novel Detection System
Nanoident Technologies AG, developer and manufacturer of printed semiconductor-based optoelectronic sensors, has entered a multiparty agreement with German company microfluidic ChipShop to develop an airborne pathogen detection system for the European Defense Agency.

The goal of the project is to develop an autonomous lab-on-a-chip based system, called the PathoID-Chip, for the detection of airborne chemical and biological agents. The system will be able to simultaneously test for multiple pathogens, in a shorter time and with greater sensitivity than is possible with conventional test methods. Tests will be completed in minutes and will be repeated every ten minutes; statistically, this is less time than it should take for a person to become infected. As a result, the presence of harmful substances can be detected in minutes and action can then be taken to reduce exposure.

To achieve these goals, the project combines several novel technologies to collect a sample from the air, inject it into liquid, process it and perform analysis. Other partners in the project include Clemens GmbH, Bundeswehr Institute of Microbiology, Friedrich-Loeffler-Institute, Joanneum Research Forschungsgesellschaft mbH, and Bertin Technologies. Nanoident’s technology is a core element of the system, and represents an advance in point-of-use testing. Because optoelectronic sensors are printed onto each chip, the system does not require laboratory handling or bulky, power-hungry, expensive optical readout equipment, making it much more portable, rugged and tolerant of dust than conventional test systems. The proximity of the sensor to the sample also results in much higher sensitivity than conventional systems.

“Our unique printed sensor technology makes it possible to develop a truly mobile detection system, offering faster detection and minimizing exposure to harmful chemical and biological agents,” said Dr. Max Sonnleitner, VP of Nanoident’s Life Sciences division.

E Ink Announces Next Generation Custom and Standard Segmented Display Cells
E Ink Corp., developer and marketer of electronic paper display technology, has released its next generation segmented display cells (SDC). The SDC products are simple digit, icon and alpha-numeric displays, offering good readability in a paper-thin form factor that uses minimal battery power. The new SDCs are 40 percent thinner with a wider operational temperature range and increased flexibility for repetitive 3-D bends or 2-D conformable solutions. Applications include consumer electronics, PC-accessory, display smartcards, capacity indicators, electronic shelf labels, signage and communications applications. The SDC displays use the same E Ink Vizplex technology that is shipping in popular electronic book devices such as the Amazon Kindle, SONY Reader and iRex iLiad.

“After an extensive review of display technologies, Delphi chose E Ink's segmented electronic paper displays for our wireless, bi-directional key fob that has been designed to offer car-to-user and user-to-car communication over an extremely long range,” said Joe DiCarlo, director of Engineering for Controls and Security in North America, Delphi. “The groundbreaking fob offers packaging flexibility and does not consume much power. Because it provides drivers valuable vehicle information and control, it is imperative that its display can be read in bright sunlight. Thanks to E Ink that is possible.”

Thinner, more flexible and wider operation ranges all highlight the performance increase of the latest generation of E Ink SDCs. Three height levels are available, depending on backplane configuration: thin PET 330 microns, PET 380 microns or PI 375 microns. PET options provide 200 micron design rules for the art work or space and trace of 8 mils by 8 mils. The finer pitch PI option uses 100 micron design rules for 4 mils by 4 mils. Increased temperature ranges with operations from -10°C to 60°C, and storage from -25°C to 75°C.

Organic non-rectangular unique shapes are possible, including holes, curves and other non-standard designs. Additionally, E Ink’s SDC platform provides viewable angle of nearly 180° and can be viewed under a variety of lighting conditions from direct sun to low-level ambient light. E Ink’s Vizplex based electronic paper solutions are bistable, reflective displays which enable the image to remain for over a year with zero power.

NanoMaterials08
July 7-9
Newcastle Marriott Hotel, UK

Following the huge success of our inaugural conference which attracted over 200 delegates, NanoCentral and IntertechPira are pleased to bring you NanoMaterials08. The only event of its kind to focus on the commercialisation of nanomaterials, NanoMaterials08 presents poster sessions, workshops, exhibitions and a conference covering the four key end users in this industry: thin film and printed electronics; nanoplastics and nanocomposites; pharmaceutical, drug delivery and personal car; and coatings, inks and pigments. With a variety of national and international companies active in the nanomaterials revolution presenting, and over 400 attendees expected, this event will provide excellent networking and learning opportunities not to be missed.

For more information please visit www.nanomaterials08.com or contact Caroline Potapa at +44 (0) 1372 802101.

May 2008

18-23 Electrochemical Society Spring, Phoenix, Ariz.

18-23 Society for Information Display 2008, Los Angeles, Calif.

19-21 19th Annual Thermal Printing Conference, Mesa, Az.

21-22 2nd RFID Technology Integration Symposium, Mesa, Az.

27-30 Electronic Components and Technology Conference 2008, Lake Buena Vista, Fla.

SEMICON West 2008
July 15-17
San Francisco, Calif.

SEMICON West 2008–Infinite Innovations, Infinite Ideas SEMICON West is the place to see the companies, technologies, and people driving the future of micro design and manufacturing. No other event this year has more new products, more new technologies, and more solutions than SEMICON West.
From the latest developments in cutting-edge materials, to the systems and technologies driving semiconductor designs to the limits of Moore's Law, you'll find everything and everyone in the industry at SEMICON West.

Registration is now open! Plan now to participate and get ready to discover the infinite opportunities shaping the design and manufacture of semiconductors, MEMS, photovoltaics, flexible electronics, and more!

For more information, visit www.semiconwest.org.

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