Isolation Die Package-in-Package Structure for High-Voltage Spacing

The patent divides the packaging structure into two distinct segments: an inner leadless package with fine pitch leads for the isolation die, and an outer lead frame package with large lead spacing for high voltage isolation. This segmentation allows each segment to be optimized independently - the inner package achieves precise manufacturing for the isolation circuitry while the outer package provides the required electrical isolation distance.

The patent implements a nested packaging structure where the leadless package containing the isolation die is placed inside the larger lead frame package. The inner package is mounted on the lead frame such that its leads connect to corresponding leads on the lead frame, creating a hierarchical nested structure that combines fine-pitch and large-spacing requirements in a single integrated package.

The packaging is segmented into functional modules: the leadless package module contains the isolation die and fine-pitch interconnections, while the lead frame module provides the external large-spacing interface. This modular segmentation reduces overall device complexity by allowing each module to be designed and manufactured independently using optimized processes for its specific function.

The nested package-in-package structure consolidates what would otherwise require two separate devices into a single integrated component. The inner leadless package is nested within the outer lead frame package, creating a compact hierarchical structure that maintains high voltage isolation while reducing the complexity of assembling and connecting multiple separate components.

The patent applies different design rules and material specifications to different regions of the package structure. The inner leadless package uses fine-pitch design rules and high-precision manufacturing processes optimized for the isolation die circuitry, while the outer lead frame uses larger design rules and standard manufacturing processes optimized for electrical isolation and external connections. This local optimization of quality standards allows each region to achieve its specific performance requirements.

By segmenting the package into inner and outer portions with different design requirements, the patent enables each segment to be manufactured using appropriately optimized processes. The inner package can use advanced fine-pitch fabrication techniques while the outer package uses more robust, easier-to-manufacture structures, thereby achieving high circuit quality where needed without sacrificing ease of manufacture overall.