3D Package Encapsulation Layout for Smooth RDL Interconnects
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving efficient integration and testing of 3D packaging structures, particularly in ensuring smooth electrical connections and minimizing surface roughness issues due to the use of encapsulant materials with large fillers, which can lead to trace breaks or shorts.
Innovation Solution
The method involves forming a package structure with a first encapsulant between and on dies, using a second encapsulant to encapsulate sidewalls, and a redistribution layer to connect conductive terminals, where the first encapsulant is free of large fillers to ensure flat surfaces and avoid roughness issues, and the second encapsulant includes fillers for lateral encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encapsulant materials with large fillers are used for lateral encapsulation, then the encapsulation effect is improved, but surface roughness increases causing trace breaks or shorts
Solution Approach 1:
The encapsulant material is segmented into two distinct types: a first encapsulant material free of large fillers for regions requiring flat surfaces (between and on dies), and a second encapsulant material containing fillers for lateral encapsulation of sidewalls. This segmentation allows each material to be optimized for its specific function, resolving the contradiction between encapsulation effectiveness and surface flatness.
Solution Approach 2:
Different regions of the package structure are assigned different encapsulant materials based on their specific requirements. The first encapsulant material (without large fillers) is applied where flat surfaces are critical for electrical connections, while the second encapsulant material (with fillers) is applied for lateral sidewall encapsulation where roughness is less critical. This local differentiation resolves the contradiction by matching material properties to functional requirements.
2Ease of manufacture
If a single encapsulant material is used for all regions, then manufacturing complexity is reduced, but electrical connection quality deteriorates due to surface roughness
Solution Approach 1:
The manufacturing process is segmented into distinct steps: forming the first encapsulant material free of large fillers in regions requiring flat surfaces for electrical connections, then forming the second encapsulant material containing fillers for lateral encapsulation. This segmentation increases manufacturing steps but ensures high electrical connection quality by preventing trace breaks and shorts through proper surface flatness.
Solution Approach 2:
The solution applies different material compositions to different spatial regions: the first encapsulant material (without large fillers) is used where electrical connections are made to ensure smooth surfaces, while the second encapsulant material (with fillers) is used for lateral encapsulation where roughness does not affect electrical performance. This local quality differentiation prioritizes electrical connection reliability.
3Strength
If encapsulant material with large fillers is used, then lateral encapsulation capability is improved, but trace integrity deteriorates due to surface roughness
Solution Approach 1:
The encapsulation system is segmented into two material types with complementary properties: the first encapsulant material provides smooth surfaces for trace integrity without compromising lateral encapsulation, while the second encapsulant material provides enhanced lateral encapsulation capability with fillers in regions where trace routing is not present. This segmentation allows both trace integrity and lateral encapsulation strength to be optimized simultaneously.
Solution Approach 2:
The solution implements local quality differentiation by applying the first encapsulant material (free of large fillers) in regions where conductive traces are present to maintain surface flatness and trace integrity, while applying the second encapsulant material (containing fillers) in lateral regions for enhanced encapsulation strength where traces are absent. This spatial differentiation resolves the contradiction between lateral encapsulation capability and trace integrity.
Data Source
AI summary
A package structure and a method of forming the same are provided. The package structure includes a first die, a second die, a first encapsulant, a second encapsulant, and a conductive terminal. The first die includes a first connector, and the second die includes a second connector. The first encapsulant includes: a first portion, on the second die; a second portion, sandwiched between a first sidewall of the first die and a first sidewall of the second die; and a third portion, covering a second sidewall of the second die. The second encapsulant, laterally encapsulating the first die, the second die and the first encapsulant. The conductive terminal, electrically connected to the first die and the second die through a redistribution layer (RDL) structure. The third portion of first encapsulant is sandwiched between the second sidewall of the second die and the second encapsulant.