Fine-Pitch Semiconductor Package Layout Without Costly Interposers

The patent transitions from a planar 2D pad layout to a 3D vertical interconnection structure. Multiple interconnection layers are stacked vertically with dielectric layers in between, allowing I/O pads to be distributed across multiple vertical levels. This dimensional transformation enables higher I/O density without increasing the lateral footprint, thereby facilitating packaging of high-density dies without proportionally increasing packaging complexity.

The patent implements nested interconnection layers where conductive structures are embedded within dielectric layers, which are in turn embedded within a substrate or package structure. The fine-pitch interconnection layers are nested within the package substrate, with each layer containing conductive traces, vias, or pads that are embedded in dielectric material. This nested arrangement allows multiple I/O connections to be packed into a compact volume, enabling high I/O density while maintaining manageable packaging dimensions and processes.

The patent replaces expensive, complex interposer structures with a cost-effective alternative: fine-pitch interconnection layers formed directly within a package substrate using standard semiconductor fabrication processes. The interconnection structure consists of conductive traces and vias embedded in dielectric layers, which can be manufactured using conventional photolithography, etching, and deposition techniques already prevalent in the industry. This approach achieves fine-pitch interconnections without requiring costly interposer materials or additional specialized manufacturing steps, thereby reducing overall manufacturing cost while maintaining the required precision.

The patent extracts the interconnection function from a separate interposer component and integrates it directly into the package substrate. Instead of using a distinct interposer layer that requires additional bonding and alignment steps, the fine-pitch interconnection layers are formed as an integral part of the substrate structure. This extraction eliminates the need for separate interposer manufacturing, handling, and assembly, thereby reducing manufacturing complexity and cost while achieving the same fine-pitch interconnection performance.