DELO: New RFID adhesive for stable jetting processes

DELO Industrial Adhesives has developed a new adhesive for the reliable bonding of RFID chips and antennas. It transmits electrical signals reliably, gives high long-term die shear strength, and enables efficient production as it can be jetted.

The global RFID market is rapidly growing. IDTechEx expect it to triple to US$ 23.4 million by the year 2020. Tag manufacturers, who sold nearly six billion items in 2013 alone, focus on cost-efficient production. Already today, one flip-chip system bonds up to 20,000 chips to antenna substrates per hour. At the same time, the trend towards miniaturization is ever-increasing also in the field of RFID labels. Their chips are often just 400x400 µm in size, which further boost the requirements imposed on the adhesive used. The surfaces for contacting and fixing are shrinking, and the adhesive must be precisely applied in minute quantities.

For this chip attach process, DELO has developed the new anisotropic conductive DELOMONOPOX AC245 adhesive. It is based on an epoxy resin and provides the utmost reliability thanks to optimized filler content. To verify the reliability, DELO subjected the bonded labels to the special 85/85 test where specimens are stored at +85 °C and 85 % relative humidity. The tag sensitivity remains at 85 percent of the initial value even after 1,000 hours under these conditions. In addition, this product is widely usable. It is suitable for the commonly used antenna substrates PET/aluminum, PET/copper or paper-based structures, and for both HF and UHF tags.

Optimized for high label output

Many of today’s labels require not more than 0.02 mg of adhesive. Therefore, most RFID manufacturers rely on adhesive jetting to achieve an efficient production process. Such minute quantities of DELO’s RFID adhesive can be dispensed through jet valves. The results achieved during a processing time of several days are both reproducible and precise. Thus, DELO’s adhesive combines high reliability and excellent processing properties. In production, this long processing time offers the advantage of shortening the cleaning intervals of the valves to minimize machine downtimes. In addition, less adhesive is wasted. When a thermode is used, the adhesive takes 8 s at 180 °C to cure, ensuring high production output.