Package-on-Package Interposer for Reduced Mounting Area
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Solution Overview
Problem
The increasing use of portable devices like smartphones and tablets requires a package-on-package (PoP) solution that reduces the mounting area on system boards without increasing the size, as traditional approaches can lead to larger system boards and reduced space for batteries.
Innovation Solution
A PoP configuration with an interposer substrate between a lower package and an upper package, featuring a first substrate with two dies side by side, a vertical connection member, and a molding layer, along with ball pads and ball lands on the upper substrate, allowing for efficient signal transmission and reduced horizontal area usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional PoP configuration is used with multiple packages mounted on a system board, then the functionality and performance of portable devices are improved, but the mounting area on the system board increases, reducing the space available for batteries
Solution Approach 1:
The patent implements a package-on-package (PoP) configuration where a first package and a second package are vertically stacked and integrated into a single mounting footprint on the system board. The lower package serves as the base layer while the upper package is positioned directly above it, allowing both packages to occupy the same horizontal mounting area. This nesting approach enables multiple functional components to be combined within a compact vertical arrangement, thereby improving device functionality without increasing the system board's mounting area.
Solution Approach 2:
The patent transitions from a traditional horizontal arrangement of multiple packages on the system board to a vertical three-dimensional configuration. By stacking packages in the vertical dimension rather than arranging them side-by-side in the horizontal plane, the invention reduces the footprint area required for mounting while maintaining the functional capabilities of multiple packages. This dimensional change allows the system to accommodate more components within the same board area.
2Area of stationary object
If the ball map configuration is constrained by overlapping signal paths between upper and lower packages, then the mounting area is reduced, but the design flexibility and ease of manufacture are worsened
Solution Approach 1:
The patent introduces an interposer substrate positioned between the upper package and the lower package to mediate the electrical connections. The interposer provides a separate layer of ball lands that can be independently configured from the ball pads on the upper package substrate. This intermediary structure allows the ball map of the upper package to be optimized for its functional requirements without being constrained by the signal path requirements of the lower package, as the interposer absorbs and redistributes the connection requirements between the two packages.
Solution Approach 2:
The patent divides the connection interface into multiple independent segments: ball pads on the upper package substrate, ball lands on the interposer substrate, and separate signal path routing. This segmentation allows each layer to be independently designed and optimized. The upper package's ball map can be configured based on its specific functional needs while the interposer handles the signal routing to the lower package, eliminating the need for overlapping constraints and improving design flexibility.
Data Source
AI summary
Provided is a package-on-package (PoP). The PoP includes a lower package, an upper package on the lower package, an interposer substrate disposed between the lower package and the upper package, and a plurality of balls connecting the interposer substrate to the upper package, in which the lower package includes a first substrate, and a first die and a second die disposed side by side in a horizontal direction, on the first substrate, in which the upper package includes a second substrate, a third die on the second substrate, and a plurality of ball pads disposed on a surface of the second substrate, the interposer substrate comprises on a surface thereof a plurality of ball lands to which a plurality of balls are attached, and at least some of the plurality of ball lands overlap the first die and the second die in a vertical direction that intersects the horizontal direction.