AIST Manufactures Radio Frequency ID Tags on Flexible Substrates Using an Entire Printed Method; Technique will Fabricate Low-cost Tags.

Tokyo, Japan, Oct 21, 2005 - (JCN Newswire) - AIST has announced a technique to fabricate radio frequency (RF) ID tags entirely by printing. AIST developed a pressure annealing method, by which the electrical resistance of antennas, wirings, and electrodes formed by screen printing can be decreased by more than three orders of magnitude. We have also made it possible to fabricate highly sensitive RF tags using the printing method without high-temperature baking. AIST has confirmed that the fabricated tags are highly response to RF signals at a range of frequencies between 5 and 40 MHz.

The National Institute of Advanced Industrial Science and Technology (AIST) has developed a method which can drastically reduce the electrical resistance of antennas, wirings etc., of radio frequency (RF) ID tags formed by screen printing. This method is one where, after printing the antenna and wiring with metallic inks, a pressure annealing process is applied to them without high temperature baking. Using this technique, we have succeeded in fabricating RF ID tags on flexible substrates entirely by printing. This indicates that high-sensitive RF tags can be formed on flexible substrates such as plastics entirely by printing, and thus a further reduction in the cost of the tags can be facilitated. This will induce the acceleration of widespread use of the tags.

RF ID tags are terminals which give and receive information by RF signals, by which existence of and information about objects can be recognized and administrated. Because of their convenience, widespread use of the tags is expected, but their high manufacturing cost is an obstacle at present. Thus the establishment of low-cost fabrication techniques of the tags is urgently needed. Techniques for fabricating the tags entirely by printing have been investigated to resolve this problem, but none have been established yet.

AIST developed a "pressure annealing" technique to reduce the resistance of conducting circuits formed on plastic film substrates by printing, without high temperature baking. Antenna circuits created by this method showed a sensitivity similar to that of antennas produced by a commercial vacuum processing technique. Moreover, using our technique, we have confirmed that RF ID tags fabricated entirely by screen printing, applying our technique, can work well at frequencies of 5-40 MHz.

The pressure annealing method is applicable to the fabrication of the wirings and electrodes on flexible substrates, such as plastic films, by printing, because even if the baking of conducting inks is done at temperatures below 200 C, their resistance can be sufficiently lowered. We expect that the method developed may be applied for various devices to manufacture low-cost, flexible ubiquitous information terminals.

A part of this study was presented at the 66th Meeting of the Japan Applied Physics Society in autumn 2005, held from September 7 to 11 in Tokushima Prefecture.

Recently, RF ID tags have attracted a great deal of attention as information terminals which can administer information of objects. They can give, receive, and control information about the objects by RF waves without being in contact with detectors, and can also be remotely-controlled, and they can display their ability for immediate administration of object information. Already, the tags are partially being used routinely, e.g., in the electronic toll collection systems of various transportation facilities. For convenience, RF ID tags have been purposed to be applied to price and baggage tags of general products to administrate their prices and logistics, but the high manufacturing cost of the terminal devices is an obstacle to promoting their widespread use.

Thus, if the RF ID tags can be fabricated entirely by printing, they can be prepared together with commercial products (to which the tags are attached) at the time of fabrication, as well the bar codes used at present, and a substantial manufacturing cost reduction can be expected. However, many problems still remain, without sufficient perspective. For example, the devices need to be formed on film substrates such as plastics, because the products to which the devices are attached have various shapes, and in addition they are often distributive ones. Component materials for the RF ID tags, such as conductive inks, mostly require a high temperature baking process after printing to obtain high conductivity. However, for the substrates of general-purpose plastics, the high temperature processing is not applicable to them; the temperature is, at the highest, 200 C. Thus, so far, it has been difficult to make good use of devices fabricated entirely by printing.

AIST has developed a technique which can reduce the resistance of conductive materials printed on substrates as antennas and wirings without high temperature baking. Furthermore, applying this technique, AIST has developed a method to fabricate RF ID tags by screen printing.

Details of the research are availavle at the AIST website:

http://www.aist.go.jp/aist_e/latest_research/2005/20051019/20051019.html

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