Package-on-Package Underfill Venting for Interconnect Reliability
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Solution Overview
Problem
There is a need for integrated circuit packaging systems that are thinner, with simplified manufacturing, reduced size, improved reliability, and increased functionality, while maintaining performance and speed, which existing technologies have not adequately addressed.
Innovation Solution
The system includes a bottom package with a cavity and vents on the inter-package connection side, allowing for the application of underfill through these vents to the cavity, which supports the mounting of a top package and enhances inter-package interconnect reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional packaging methods are used, then manufacturing is simpler, but packaging reliability is reduced due to inadequate underfill distribution
Solution Approach 1:
The bottom package structure is segmented to include a separate cavity and vent channels, dividing the underfill delivery system into distinct components that enable controlled material flow while maintaining overall package integrity
Solution Approach 2:
The vent structure acts as an intermediary element between the exterior environment and the internal cavity, mediating the underfill flow to achieve uniform distribution throughout the cavity while protecting the interconnects
2Volume of moving object
If package size is reduced to meet miniaturization demands, then product size decreases, but manufacturing precision requirements increase
Solution Approach 1:
The cavity and vent structures are nested within the existing bottom package footprint, utilizing the available space efficiently to create the underfill delivery system without increasing the overall package dimensions
Solution Approach 2:
The vent dimensions and cavity geometry are optimized as specific parameters to control underfill flow characteristics, allowing precise material distribution even in miniaturized package configurations
3Reliability
If underfill is applied to protect interconnects, then reliability improves, but manufacturing process complexity increases
Solution Approach 1:
The cavity and vent structures are pre-formed in the bottom package before underfill application, preparing the delivery pathway in advance to simplify the actual underfilling process and ensure uniform distribution
Solution Approach 2:
The vent structure enables self-regulating underfill flow through capillary action and pressure equalization, allowing the system to automatically control material distribution without requiring complex external dispensing equipment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient underfilling, increasing packaging reliability by ensuring equal distribution and flow of the underfill, thus protecting inter-package interconnects from corrosion and structural damage, while reducing manufacturing complexity and costs.
Implementation Method 1
applying an underfill through the vent and into the cavity
Data Source
AI summary
A method of manufacturing of an integrated circuit packaging system includes: providing a bottom package in a cavity in a central region of the bottom package having inter-package interconnects in the cavity; forming a vent on an inter-package connection side of the bottom package from an exterior of the bottom package to the cavity; mounting a top package on the inter-package interconnects; and applying an underfill through the vent and into the cavity.