Many integrated circuit (“IC”) device packages utilize a metal leadframe to provide electrical interconnects between an integrated circuit die and external components. Such leadframes generally include numerous metal leads that extend away from a die and that are contained within the same general plane, so as to facilitate the ready manufacture of the same leadframe in mass quantities. Many leadframes also include a die attach pad (“DAP”) within the same general plane as the metal leads, typically at or near their center. The DAP can support the die during assembly of the package, provide a ground or other electrical contact for the package, and can also help with thermal management of the package by providing a good thermal conduction path for dissipating excess heat generated by the die.
While early leadframe designs typically provided a DAP and metal electrical leads for a single die, technological advances have resulted in more complex components than single die packages. Complex components that can utilize leadframes include, for example, the multi-chip module (“MCM”) and system in package (“SIP”) IC arrangements, among others. Both MCMs and SIPs can have multiple chips and/or other components all within a single package, which tends to result in savings in both space and cost with respect to traditional arrangements that would include all of the same or similar chips or components, typically spread out across multiple packaged components.
Although MCMs and SIPs represent improvements over simpler conventional IC designs, these relatively complex devices do require many electrical contacts in a restricted amount of space. The generally planar nature of a traditional single leadframe, when combined with this complexity of an MCM or SIP, can result in a sophisticated device that still has a rather large footprint in comparison with other IC devices. As will be generally understood, it is typically not desirable to have IC devices that present relatively large footprints, particularly when it comes to portable devices, such as cellular telephones, personal digital assistants, media play devices, and the like. IC device packages that result in smaller device footprints are generally desirable, since smaller device footprints tend to result in greater assembly yields and reduced unit costs. Examples of packages that utilize more advanced leadframe structures, such as for more complex IC arrangements, can be found at, for example, U.S. Pat. Nos. 5,994,768; 6,072,228; and 6,215,176, among other similar references. Of course, the introduction of multi-layer and/or multi-part leadframe structures, such as those in the foregoing references, tends to result in additional problems and issues that are not found in simpler leadframe arrangements.
While many of the devices and techniques used to package IC devices have generally worked well in the past, there is always a desire to provide improved ways for packaging IC devices. In particular, complex leadframe based packages for MCMs, SIPs or other complex IC structures that provide reliable performance within a relatively small overall footprint are desired.