Through-Assembly Via Modules for High-Density Package-on-Package Interconnects
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Solution Overview
Problem
In conventional Package-on-Package (POP) processes, the large size and limited number of solder balls restrict the integration level due to their height and lateral dimensions, which hinders efficient connection between the top and bottom packages.
Innovation Solution
The implementation of Through-Assembly Via (TAV) modules, which include pre-formed substrates with penetrating through-substrate vias and metal posts, allows for precise electrical coupling and increased connection density by replacing large solder balls with smaller, densely packed through-substrate vias and metal posts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solder balls are used to connect top package to bottom package, then electrical connection is achieved, but the large size and limited number of solder balls restrict the integration level
Solution Approach 1:
The connection structure is segmented into multiple components: through-substrate vias penetrating the substrate, metal posts within the vias, and solder balls on top of the metal posts. This segmentation allows each component to perform its specific function optimally while achieving higher connection density overall
Solution Approach 2:
The connection structure transitions from a two-dimensional solder ball arrangement to a three-dimensional structure with through-substrate vias extending vertically through the substrate. This dimensional change enables multiple connection points within a smaller lateral footprint, increasing connection density
2Length of moving object
If solder ball height is increased to protrude above device die, then connection is achieved, but the lateral sizes of solder balls become large
Solution Approach 1:
The metal posts are nested within the through-substrate vias, and solder balls are placed on top of the metal posts. This nested arrangement allows the connection structure to achieve greater effective height while maintaining a compact lateral footprint, as each component is contained within or upon the previous component
3Quantity of substance
If number of solder balls is increased, then connection density improves, but the available space is limited due to large lateral sizes
Solution Approach 1:
The connection structure is segmented into multiple components: through-substrate vias penetrating the substrate, metal posts within the vias, and solder balls on top of the metal posts. This segmentation allows each component to perform its specific function optimally while achieving higher connection density overall
Solution Approach 2:
The connection structure transitions from a two-dimensional solder ball arrangement to a three-dimensional structure with through-substrate vias extending vertically through the substrate. This dimensional change enables multiple connection points within a smaller lateral footprint, increasing connection density
Data Source
AI summary
A device includes a Through-Assembly Via (TAV) Module, which includes a substrate, a plurality of through-vias penetrating through the substrate, and a second plurality of metal posts at a bottom surface of the TAV module and electrically coupled to the plurality of through-vias. A polymer includes a first portion between and contacting sidewalls of the first package component and the TAV module, a second portion disposed between the first plurality of metal posts, and a third portion disposed between the second plurality of metal posts. A first plurality of Redistribution Lines (RDLs) is underlying a bottom surface of the second and the third portions of the polymer. A second plurality of RDLs is over the first package component and the TAV module. The first plurality of RDLs is electrically coupled to the second plurality of RDLs through the plurality of through-vias in the TAV module.