Development of Chip to Antenna Interconnections for Contact-less Smart Card Applications

摘要

In contact-less smart cards the interconnection is usually made from packaged chip module to the antenna using soldering, welding or adhesive bonding. Because the chip itself is usually wire bonded to the module substrate, there are two levels of interconnection as well as two different substrates: antenna substrate and module substrate. Because in smart card markets there is a trend towards thinner, flexible, durable and cost efficient structures, there is a need to develop interconnection methods which allow reliable interconnection of thinned silicon chips directly onto thin flexible substrates. Various technologies of antenna manufacturing as well as methods for integration of thinned chips are discussed. Experimental results for interconnections made using anisotropically conductive adhesives (ACA) and non conductive adhesives (NCA) are reported. Some critical issues of interconnections including substrate materials, adhesive dispensing methods, curing temperatures, bonding force and surface roughness of antenna pad areas are discussed.