Stackable Multi-Chip Package with Die-Attach Paddle for Thermal Management
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Solution Overview
Problem
Current stackable integrated circuit packages face challenges in achieving low cost manufacturing, improved reliability, increased thermal performance, and robust structural support while managing electromagnetic interference (EMI) and warpage, with existing solutions failing to provide a thin profile and high yield.
Innovation Solution
A stackable multi-chip package system is designed with an external interconnect having a base and a tip, mounting integrated circuit dies in an active side to active side configuration, connecting them to the base, and molding with the interconnect partially exposed to enhance thermal dissipation and structural integrity, using a die-attach paddle for multiple functions including heat management and EMI shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If packages are stacked to increase integration density, then the number of circuits and functions increases, but the package thickness increases and warpage becomes more severe
Solution Approach 1:
The patent transitions from planar packaging to three-dimensional stacking architecture, arranging multiple chip packages vertically in stacked layers. This dimensional change enables higher integration density by utilizing the Z-axis space, allowing multiple functional circuits to be packaged within a smaller footprint area while maintaining controlled thickness through optimized layer stacking.
Solution Approach 2:
The patent implements nested packaging where smaller chip packages are stacked within and upon larger package structures. Multiple chip packages are arranged in a hierarchical stacking pattern, with lower layers providing support and upper layers adding functional capacity, enabling dense integration while maintaining overall structural compactness and controlled thickness.
2Adaptability or versatility
If more circuits are packed into integrated circuits, then functionality increases, but heat generation increases and reliability decreases
Solution Approach 1:
The patent introduces intermediate thermal management structures between stacked chip packages, including thermal vias, heat spreaders, and thermally conductive materials in the stacking layers. These intermediary elements facilitate heat transfer from high-power density regions to heat sinks and cooling structures, maintaining reliable operation temperatures despite increased circuit density and functionality.
Solution Approach 2:
The patent employs parameter changes in material selection and structural design to manage thermal characteristics. Different materials with varying thermal conductivities are used in different layers, and structural parameters such as via diameter, layer thickness, and spacing are optimized to control heat flow paths, enabling high functionality while maintaining reliability through thermal management.
3Productivity
If stacking features are added to enable package stacking, then integration density increases, but manufacturing complexity increases and structural integrity becomes difficult to control
Solution Approach 1:
The patent incorporates stacking features and alignment structures during the initial package fabrication process rather than adding them later. Mounting protrusions, engagement features, and alignment marks are formed as integral parts of the package structure during molding and assembly, enabling subsequent stacking operations to proceed with simplified processes and reduced manufacturing complexity.
Solution Approach 2:
The patent divides the stacking structure into modular segments with standardized interfaces. Each chip package contains discrete mounting features and connection elements that can be independently manufactured and then assembled into the final stacked configuration. This segmentation enables parallel manufacturing of individual packages followed by systematic assembly, reducing overall manufacturing complexity while achieving high integration density.
4Temperature
If external heat sinks are added to improve thermal performance, then heat dissipation increases, but package footprint increases and structural integrity decreases
Solution Approach 1:
The patent employs thin-film heat spreaders and flexible thermal management layers integrated within the package structure. These thin thermal management elements provide effective heat dissipation pathways without adding significant footprint, as they conform to the package geometry and distribute heat laterally across existing surface areas rather than requiring additional external heat sink structures.
5Adaptability or versatility
If more circuitry is packed into integrated circuits, then functionality increases, but electromagnetic interference increases and performance degrades
Solution Approach 1:
The patent extracts and separates high-frequency signal paths and sensitive circuitry into distinct packaging layers and isolation zones. By physically separating interfering signal paths from sensitive circuits through the vertical stacking architecture and using dedicated shielding layers between packages, electromagnetic interference is contained and prevented from degrading overall system performance despite increased functionality.
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
The solution provides a thin package with enhanced thermal performance, structural rigidity, high land count, and flexible connection options, addressing the limitations of existing technologies by ensuring reliable and cost-effective manufacturing with improved reliability and EMI mitigation.
Implementation Method 1
Every new generation of integrated circuits with increased operating frequency, performance and the higher level of large scale integration have underscored the need for back-end semiconductor manufacturing to increase the heat management capability within an encapsulated package
Implementation Method 2
As more functions are packed into the integrated circuits and more integrated circuits into the package, more heat is generated degrading the performance, the reliability, and the lifetime of the integrated circuits. As more circuitry is packed into the integrated circuits, the integrated circuit generates more radiated energy called electromagnetic interference (EMI)
Data Source
AI summary
A stackable multi-chip package system is provided including forming an external interconnect, having a base and a tip, and a paddle; mounting a first integrated circuit die over the paddle; stacking a second integrated circuit die over the first integrated circuit die in a active side to active side configuration; connecting the first integrated circuit die and the base; connecting the second integrated circuit die and the base; and molding the first integrated circuit die, the second integrated circuit die, the paddle, and the external interconnect with the external interconnect partially exposed.