Open Cavity Interposer for Semiconductor Die Thermal Management
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Solution Overview
Problem
Current semiconductor devices face challenges in heat dissipation and warpage due to the mismatch in thermal expansion coefficients between stacked semiconductor dies and organic substrates, and they struggle with fine-pitch die integration and bump collapse issues in wafer level chip scale packages.
Innovation Solution
The development of a semiconductor device with an open cavity interposer that uses Through Silicon Vias (TSVs) and conductive pillars for improved thermal management and interconnectivity, along with a polymer insulating layer and EMI/RFI shielding, to enhance heat dissipation and reduce warpage and bump collapse risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If stacked semiconductor dies are mounted over an organic substrate, then device integration is increased, but heat dissipation becomes difficult and warpage occurs due to CTE mismatch
Solution Approach 1:
The invention divides the package structure into distinct segments: an open cavity interposer with a cavity, a first semiconductor die mounted in the cavity, and a second semiconductor die stacked over the first die. This segmentation allows the thin lower die to be contained within the cavity while the interposer provides separate thermal management pathways, enabling effective heat dissipation even as device integration increases through stacking.
2Strength
If a fixed organic substrate is used, then structural support is provided, but handling damage occurs to thin semiconductor die and warpage is caused by CTE mismatch
Solution Approach 1:
The invention introduces an open cavity interposer as an intermediary component between the semiconductor dies and the organic substrate. This interposer acts as a mediator that provides mechanical support and protection during handling, while its open cavity design and material properties help accommodate CTE differences, reducing warpage. The interposer protects the thin lower die from damage during handling while maintaining structural integrity of the overall package.
3Reliability
If large diameter bumps are used in FO-WLCSP, then electrical connection is achieved, but bump collapse is difficult to control and fine-pitch die integration is limited
Solution Approach 1:
The invention applies local quality by providing mechanical support specifically to the bumps and die regions that require it, rather than uniformly increasing substrate rigidity throughout. The open cavity interposer structure provides localized support to the lower die and bumps, enabling better control of bump collapse during reflow while maintaining the ability to achieve fine-pitch interconnections. This localized support approach allows electrical connection reliability to be improved without sacrificing manufacturing precision for fine-pitch die integration.
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 solution enables efficient heat dissipation, reduces warpage, and allows for finer pitch and higher I/O count integration, improving the reliability and performance of semiconductor devices by addressing thermal and mechanical challenges in wafer level chip scale packages.
Implementation Method 1
uses Through Silicon Vias (TSVs) and conductive pillars for improved thermal management
Implementation Method 2
along with a polymer insulating layer and EMI/RFI shielding
Implementation Method 3
along with a polymer insulating layer and EMI/RFI shielding
Data Source
AI summary
A semiconductor device has an interposer mounted over a carrier. The interposer includes TSV formed either prior to or after mounting to the carrier. An opening is formed in the interposer. The interposer can have two-level stepped portions with a first vertical conduction path through a first stepped portion and second vertical conduction path through a second stepped portion. A first and second semiconductor die are mounted over the interposer. The second die is disposed within the opening of the interposer. A discrete semiconductor component can be mounted over the interposer. A conductive via can be formed through the second die or encapsulant. An encapsulant is deposited over the first and second die and interposer. A portion of the interposer can be removed to that the encapsulant forms around a side of the semiconductor device. An interconnect structure is formed over the interposer and second die.