Novel Multi Chip Packaging Method Using Stochastic Self Assembly

The objective of this project was to apply a self-assembly process in the development of a functional battery assisted passive (BAP) tag. A multifunctional sensor using RF signals was designed and fabricated. Multiple ASIC and OTS IC dice were placed in a multi layer flexible carrier by applying a self assembly method and packaged to archive inexpensive micro sensors. The interconnections were made using printable conductive inks to replace previously used thin film processes and to reduce costs. This flexible package consists of more than one polymer substrate with the devices embedded in it and connected to each other and are finally covered by polymeric pla-narization layers where the traces are printed on leading to the package terminal of the device.

The RF system can receive an RF signal, store the required info, and respond to stored information when prodded to do so through an RF signal. The flexible package consists of a polymer substrate with the device embedded in it and covered by a polymer. The polymer cover layer protects and sandwiches the device between the substrate and itself. The interconnection from the chips to the package terminals is provided using vias in the cover-lay polymer. The package terminals on the cover-lay surface interconnect with the device through the vias in the cover-lay over the terminals on the device. Metallization is accomplished using a photolithography process.