Segmented PoP Molding Member for Thermal Stress Reduction
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Solution Overview
Problem
Package-on-package (PoP) modules face challenges in reducing thickness while minimizing stress on connection members due to thermal expansion differences between substrates and molding materials, leading to potential warpage and reliability issues.
Innovation Solution
The PoP module design incorporates an upper molding member divided into separate parts by trenches and a supporting rib to reduce thermal stress on connection members, improving reliability by mitigating warpage and thermal expansion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If thin semiconductor chips are used to reduce PoP module thickness, then the thickness is reduced, but warpage increases causing stress on connection members
Solution Approach 1:
The upper molding member is divided into multiple separate molding members by trenches, creating segmented structures that can independently accommodate thermal expansion and reduce warpage-induced stress on connection members while maintaining thin profile
Solution Approach 2:
Different regions of the package structure are given different properties - the molding members are separated into discrete units with specific trench geometries that locally manage stress distribution and thermal expansion characteristics to prevent warpage
2Ease of manufacture
If molding members are made as single continuous structure, then manufacturing is simpler, but thermal expansion stress concentrates causing warpage
Solution Approach 1:
The continuous molding member is segmented into multiple separate molding members through trenches, allowing each segment to independently manage thermal expansion and reduce warpage stress while remaining manufacturable through standard molding processes
3Reliability
If connection members are subjected to thermal stress from warpage, then electrical connections may fail, but adding support structures increases complexity
Solution Approach 1:
The support structure is achieved through simple trenches that segment the molding member into separate units, providing warpage management and connection member protection without requiring complex additional support components
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 design effectively reduces stress on connection members, enhancing the reliability of PoP modules by minimizing thermal expansion-induced warpage and maintaining module stability across temperature variations.
Implementation Method 1
thermal expansion differences between substrates and molding materials, leading to potential warpage and reliability issues
Implementation Method 2
The warpage of the semiconductor packages in the PoP modules may produce a stress in connection members
Data Source
AI summary
Package-on-package (PoP) modules are provided. The PoP module includes a lower package and an upper package disposed over the lower package. The lower package includes a lower substrate and a lower chip disposed over a top surface of the lower substrate. The upper package includes an upper substrate, a plurality of upper chips disposed over a top surface of the upper substrate, and an upper molding member disposed over the plurality of upper chips. The upper molding member is divided into at least two parts which are separated from each other by a trench. Related memory cards and related electronic systems are also provided.