QFN Multi-Level Pin Routing:Innovative Design Approach Enabling Complex Wire Bonding Layout

One of the most complicated process in semiconductor packaging is wire bonding. Not only is wire bonding process dynamic due to varying conditions and parameters, complex wire layout with use of multiple and thin wires laid out on a single layered lead frame makes it more difficult. Challenges posed by this process and material combinations hinder the opportunity to grow and gain more of the market, especially in high pin-count QFN package. This paper will discuss QFN multi-level pin routing, an innovation in QFN lead frame design which will enable complex wire bonding layout for high pin-count QFN packages. This design provides elevated bonding sites positioned to avoid wire sweeps, sags, risks of short circuits and other damages which are attributed to complex wire layouts. Signals from the bond sites can be routed to the package leads by the multilevel leadframe, providing a cost effective and highly manufacturable package.