Stacked Semiconductor Package With Hollowed Substrate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor packaging using peripheral solder ball z-interconnects limits the number of connections, design flexibility, and increases package thickness and cost due to the need for larger solder balls and increased substrate area, making it impractical for stacked die configurations.
Innovation Solution
A stackable semiconductor package with a 'hollowed' substrate that accommodates a mold cap without contact, featuring a frame substrate with an opening for the mold cap and z-interconnect ball pads, allowing for smaller diameter solder balls and increased interconnection density without additional substrate area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peripheral solder ball z-interconnects are used in stacked packages, then electrical connection between packages is achieved, but the number of connections is limited and substrate area increases
Solution Approach 1:
The patent transitions from peripheral solder ball connections (2D arrangement at package edges) to through-substrate vias (3D arrangement penetrating the substrate). This dimensional change allows interconnects to be distributed across the entire substrate area rather than confined to the periphery, dramatically increasing the number of possible connections without expanding the package footprint.
Solution Approach 2:
The patent divides the interconnection function into multiple discrete through-substrate via locations distributed across the substrate. Instead of concentrating connections at peripheral edges, the via connections are segmented and distributed throughout the substrate area, enabling higher interconnection density while maintaining a compact package footprint.
2Reliability
If peripheral solder ball z-interconnects are used, then package assembly is achieved, but package thickness increases
Solution Approach 1:
The patent replaces the tall, peripheral solder ball interconnect structure with compact through-substrate via connections that penetrate directly through the substrate thickness. This eliminates the need for extended peripheral connection structures, thereby reducing overall package thickness while maintaining reliable electrical interconnection between stacked packages.
3Reliability
If peripheral solder ball z-interconnects are used, then z-interconnection is achieved, but design flexibility is limited
Solution Approach 1:
The patent segments the interconnection architecture into multiple independently configurable via locations distributed across the substrate. This segmentation allows different via patterns, densities, and arrangements to be implemented based on specific design requirements, enabling greater adaptability for different package configurations, interconnection needs, and application requirements compared to the fixed peripheral solder ball arrangement.
Data Source
AI summary
A stackable package substrate has an opening shaped and dimensioned to accommodate but not contact a mold cap of a package upon which the stackable package is to be mounted. On the die attach surface, the frame substrate accommodates a die attach margin adjacent at the edge of the opening; and a row of wire bond sites arranged along at an outer frame edge, for electrical interconnection. The frame substrate accommodates z-interconnect ball pads arranged to align with corresponding z-interconnect pads on the substrate of a package. A stackable package has a frame substrate. A stacked package assembly includes a second package mounted on a first package using peripheral solder ball z-interconnect, in which the first package includes a die enclosed by a mold cap and in which the second package includes one die mounted on the frame substrate.