High Volume, Low Cost Flip Chip Assembly on Polyester Flex

Polymer Thick Film (PTF) technology provides the lowest cost, cleanest and most efficient manufacturing method for producing flexible circuits. PTF is a 100% additive process capable of applying conductors, resistors and dielectrics directly to a substrate. SMD components can be assembled using low temperature process conductive adhesives making the PTF system compatible with the most temperature-limited flexible films and components. Millions of SMT assemblies are built with PTF flexible circuits every year. Non-contact radio frequency (RF) Smart Cards and related information transaction devices, such as RFID tags, appear to be a good fit for PTF-Flex. Flip Chip also seems well suited for these “contactless” RF transceiver products since it offers the ultimate in miniaturization, minimum profile, and low cost potential. Flip Chip and PTF adhesive technologies are highly compatible and synergistic. All PTF SMT adhesives assembly methods are viable for Flip Chip. These include isotropic pastes, anisotropic films and pastes and even non-conductive systems. However, the merging of Flip Chip with PTF-Flex presents major challenges in design, materials and processing. This paper will compare assembly methods and discuss obstacles and solutions for state-of-the-art Flip Chip on Flex within the RFID product environment.