Package-on-Package Assembly With Partial Through-Mold-Vias
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Solution Overview
Problem
Existing Package-on-Package (PoP) assemblies face challenges with tight pitch stacking, large form factor, and poor warpage control, necessitating a more compact and fine pitch PoP assembly with improved manufacturing methods.
Innovation Solution
A PoP assembly design featuring a bottom die package with an interposer, chip mounting through bumps, molding compound, and peripheral bump structures comprising conductive pillars and partial Through-Mold-Vias (TMVs), along with solder balls on the interposer side, enabling electrical connection and reduced form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If prior art PoP assembly uses peripheral solder balls or through mold vias for interconnection, then electrical connection between packages is achieved, but the pitch stacking cannot be tight and the form factor becomes large
Solution Approach 1:
The invention transitions from planar interconnection (peripheral solder balls) to vertical interconnection (through-mold vias extending through the molding compound). This dimensional change enables tighter pitch stacking by utilizing the vertical dimension for signal transmission, thereby reducing the horizontal footprint and overall form factor of the PoP assembly.
Solution Approach 2:
The through-mold vias are nested within the molding compound, with conductive structures embedded inside the encapsulant material. This nesting approach allows interconnection elements to be contained within the package volume rather than extending externally, reducing the overall form factor while maintaining electrical connectivity.
2Stability of the object's composition
If prior art PoP assembly uses traditional interconnection methods, then package assembly is achieved, but warpage control is poor
Solution Approach 1:
The invention implements localized reinforcement structures within the molding compound, specifically the through-mold vias with conductive pillars that provide structural support at critical interconnection points. This local quality enhancement strengthens the package assembly at stress concentration areas, improving overall warpage control without requiring changes to the entire manufacturing process.
3Area of stationary object
If tight pitch stacking is implemented in PoP assembly, then smaller footprint is achieved, but manufacturing complexity increases
Solution Approach 1:
The interconnection structure is segmented into distinct functional components: through-mold vias for vertical signal transmission, conductive pillars for electrical connection, and peripheral bump structures for additional interconnectivity. This segmentation allows each component to be optimized independently and facilitates modular manufacturing processes, reducing overall manufacturing complexity despite the tight pitch design.
Data Source
AI summary
A package-on-package (PoP) assembly includes a bottom die package and a top die package mounted on the bottom die package. The bottom die package includes an interposer having a first side and a second side opposite to the first side, at least one chip mounted on the first side within a chip mounting area through a plurality of bumps, a molding compound disposed on the first side, the molding compound covering the at least one chip, and a plurality of peripheral bump structures penetrating through the molding compound within the peripheral area. Each of the peripheral bump structures includes conductive pillar and a partial TMV directly stacked on the conductive pillar. A plurality of solder balls is mounted on the second side of the interposer. The top die package is electrically connected to the peripheral bump structures.