Fan-Out Package Structure for High-Density PoP Interconnects
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving compact and efficient packaging of electronic components due to the increasing complexity and miniaturization of integrated circuits, which requires innovative methods for manufacturing package structures that enhance integration density and reduce area usage while maintaining reliability and connectivity.
Innovation Solution
The method involves forming a package structure using a carrier with a de-bonding layer, a redistribution layer (RDL) with multiple polymer and conductive layers, and a die connected via conductive bumps, followed by encapsulation and the formation of through integrated fan-out vias (TIVs) and protection layers to control warpage and facilitate electrical connections, allowing for the creation of compact and reliable package-on-package (PoP) devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If continuous reductions in minimum feature size are implemented to increase integration density, then more electronic components can be integrated into a given area, but the package size must be reduced accordingly to accommodate smaller components
Solution Approach 1:
The patent implements integrated fan-out packaging that extends electrical connections in the lateral dimension through TIV structures, allowing signals to route outside the die footprint. This dimensional extension enables higher integration density without proportionally reducing package area, as connections utilize the planar space around the die rather than being confined to vertical through-holes.
Solution Approach 2:
The packaging structure is segmented into distinct functional layers including carrier substrate, redistribution layers, encapsulant, and TIV structures. This segmentation allows independent optimization of each layer - the carrier provides mechanical support, RDLs provide routing, and TIVs provide external connections - enabling high integration density while maintaining adequate package area for heat dissipation and signal integrity.
2Reliability
If complex multi-layer RDL structures with multiple polymer and conductive layers are formed to achieve efficient electrical redistribution, then connectivity is improved, but the manufacturing process complexity increases
Solution Approach 1:
The redistribution layers serve multiple functions simultaneously: they provide electrical connectivity between die pads and package terminals, enable signal routing around the die perimeter through TIVs, provide mechanical strain relief, and offer thermal management pathways. This multi-functionality reduces the need for separate dedicated structures, simplifying the overall manufacturing process despite the multi-layer complexity.
Solution Approach 2:
The patent introduces encapsulant material as an intermediary that bonds the die to the carrier substrate and provides a matrix for forming TIV structures. This encapsulant mediates between the rigid die and carrier, allowing flexible routing of TIVs while maintaining structural integrity. The de-bonding layer acts as another intermediary that enables controlled release of the die from the carrier after bonding, simplifying the assembly process.
3Area of stationary object
If through integrated fan-out vias (TIVs) are formed to enable lateral electrical connections outside the die area, then area usage is reduced, but warpage control becomes more challenging
Solution Approach 1:
The patent employs a carrier substrate with specific mechanical properties that acts as a counterweight to the warpage forces generated by TIV formation and encapsulant curing. The carrier's rigidity and thermal expansion characteristics are selected to compensate for stress buildup during processing, maintaining planarity despite the complex multi-layer structure and lateral routing requirements.
Data Source
AI summary
A method of forming a package structure includes the following steps. A first package structure is formed. The first package structure is connected to a second package structure. The method of forming the first package structure includes the following steps. A redistribution layer (RDL) structure is formed. A die is bonded to the RDL structure. The RDL structure is electrically connected to the die. A through via is formed on the RDL structure and laterally aside the die. An encapsulant is formed to laterally encapsulate the through via and the die. A protection layer is formed over the encapsulant and the die. A cap is formed on the through via and laterally aside the protection layer, wherein the cap has a top surface higher than a top surface of the encapsulant and lower than a top surface of the protection layer. The cap is removed from the first package structure.