Leonhard KURZ (KURZ), based in Germany, is one of the international market leaders in the field of research, development, manufacture and supply of foils, printed products and related application technology. The company has more than 3,000 employees, as well as nine production facilities located throughout Europe, the US and the Pacific region.
While most investment in printed electronics has been by material companies, KURZ is one of the few printing companies that has invested significantly in the subject, bringing much needed printing expertise to the industry. KURZ is a 51% shareholder in PolyIC, the rest being owned by Siemens. PolyIC is developing roll to roll manufacturing of polymer "chips", targeting RFID applications. KURZ has also done significant work with organic photovoltaics, having a partnership with Konarka. In addition, KURZ acquired OVD Kinegram, which has optical competence which it intends to leverage with printed electronics. Few printing companies have shown such consistency and investment in printed electronics - KURZ is obviously positioning itself to become a major provider to the industry.
To further its capability, KURZ has now launched a new technology to make conductive patterns. While this is applicable to many markets, KURZ is initially focusing on RFID tag antenna manufacture, initially at HF for silicon chip tags, covering applications from smart labels to ID cards.
The technology, named SECOBO®, offers a list of benefits due to its unique Selective Copper Deposition process. Some of the benefits include:
- One step continuous web process up to 650 mm width
- Adhesiveless construction
- Selective build-up process - Cu thickness according to requirement
- Superior mechanical properties: flexible, metal to chip adhesion and overall durability
- Very sharp line resolution
Source: Kurz www.kurz-rfid.com 
Thorsten Hepp , Sales & Marketing Manager, told IDTechEx that they use gravure printing followed by a one step copper metallization process. The complete antenna is made from one piece of metal including the back side bridge. Copper is grown through punched holes in the substrate to get connectivity like a rivet. Gravure printing allows them to achieve a separation resolution of 150µm, for bond pads for example. Speed of throughput is a few meters per minute, depending on the thickness of the copper required, which can be controlled from 0 to 20µm. On the web width of 650mm, this allows for hundreds of millions of tag antennas to be produced each year.
Copper has the benefit of being much cheaper than silver, which has been used for many smart labels. However, copper oxidation has been a problem, because copper oxide is not conductive, unlike silver oxide, making the chip attach more difficult. However, by having significant expertise in coatings, KURZ has dealt with this problem by thinly coating the copper with a special liquid to prevent oxidation. Hepp says, "Copper offers excellent flip chip bonding basis, due to its surface structure, the metal itself, absence of hard aluminium oxide compared to aluminium based antennas and acid resist lacquer. Transfer resistance and mechanical strength is excellent as well. All this is most important as a precondition for long term reliability and durability."
KURZ offers a wide range of foils to the card and packaging industry, and intends to leverage these links with ready to use semi-finished products incorporating RFID inlays in cooperation with subcontractors.
KURZ is a well known brand in this field for foil on surface such as decorating, brand protection with holograms, magnetic stripes, signature field (hidden chemical functionality), scratch-off-foil, etc. This now enables KURZ to offer products for interior functions - the complete range from valuable paper tickets to access cards, banking cards to ID cards.
KURZ is already working with RFID converters such as UPM Raflatac, and is seeing significant interest from contactless smart card manufacturers, who are mainly using wire wound coils for antennas - an old, expensive technology. Hepp explains, "SECOBO is a match for wire-wound antenna manufacture in terms of performance with the advantage of continuing quality control in mass production. Other methods such as silver flake ink printing are not suitable for PVC card lamination - a series of inks melt during card lamination. There are several further aspects why other methods cannot follow SECOBO into the field of contactless smart cards with regards to lifetime requirements of 3 up to 10 years."
Using the SEBOCO process rather than wire winding allows for:
- Different substrates to be used, like PET, PVC, etc.
- Mounting a flip chip or a module on the antenna foil
- Thinner antennas - a pre-laminated core sheet less than 300µm is available (using flip chip)
Source: Kurz www.kurz-rfid.com
For more information please see www.kurz-rfid.com or hear Kurz at the IDTechEx RFID Europe event in Cambridge, UK on September 30-Oct 1.
or hear Kurz at the IDTechEx RFID Europe event in Cambridge, UK on September 30-Oct 1.