IC Package Floating Metal Lines to Prevent Underfill Cracking

The patent transitions from planar redistribution to three-dimensional vertical stacking architecture. Multiple dies are stacked vertically with interconnect structures (through-silicon vias, bump connections) enabling electrical connections between layers. This vertical dimension allows high I/O pad density on each die while providing sufficient packaging area through spatial distribution across multiple levels, effectively resolving the contradiction between functionality integration and packaging difficulty.

The patent implements a nested structure where multiple integrated circuit dies are stacked within a single package substrate. Each die contains functional circuits and I/O pads, and these dies are nested vertically with interconnect structures providing electrical pathways between nested layers. This nesting approach increases the effective I/O capacity without proportionally increasing the package footprint, addressing the packaging difficulty arising from high I/O density requirements.

The patent performs preliminary singulation of integrated circuit dies from wafers before the stacking and packaging process. This preliminary action allows individual dies to be prepared, tested, and sorted independently, then selectively stacked in desired configurations. The singulated dies are subsequently bonded to the package substrate with interconnect structures, achieving I/O redistribution without requiring complex in-situ routing modifications during final assembly.

The patent segments the integrated circuit system into multiple independent dies that can be manufactured, tested, and packaged separately. Each die is singulated as an independent unit, allowing flexible combination and stacking to achieve the desired I/O distribution pattern. This segmentation enables modular assembly and simplifies the manufacturing process compared to attempting to redistribute I/O pads on a single large die.