RELIABLE LEADFRAME DESIGN FOR CONTACTLESS SMART CARD AND PLASTIC PACKAGING
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2002-Jun-11
The radio frequency (RF) personal identifica- tion (ID) card and contactless smart card markets have been enjoying a high growth rate in the recent years. One of the issues to develop superior, low cost manufacturing technologies and capabilities is manufacturing yield (quality). Of the yield issues, interconnect (i.e., solder joint, conductive adhesive, etc.) failure or poor card surface (pitting, voiding, warpage, bow, etc.) are the two major concerns observed in the card fabrication. In the existing ID/smart card lamination process developed by Indala, an IC, a chip capacitor, a chip resistor, two leadframes, and a coil are sandwiched between two polyvinyl chloride (PVC) layers (See Figure I). During this lamination process, pressure forces exerted by the soft PVC flow, e.g. PVC tends to push the two leadframes apart (A and B in Figure 2), resulting in severe stresses in the solder joints. These process-induced stresses can easily cause the solder joint to crack.