Interposer Step Die Cavity for Dense 3DIC Interconnects and Heat Dissipation
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Solution Overview
Problem
Existing 3DIC packages face challenges in reducing the pitch of vertical interconnects to support higher I/O connections without increasing the package area, and existing methods fail to effectively dissipate heat generated by larger dies.
Innovation Solution
An interposer substrate with integrated die cavities in its outer layers, allowing dies to extend into the substrate, reducing the vertical distance and interconnect aspect ratio, and incorporating residual metal interconnects adjacent to the die cavity for enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch of vertical interconnects is reduced to support higher I/O connections, then the I/O density increases, but the aspect ratio of vertical interconnects increases making fabrication difficult
Solution Approach 1:
The patent introduces a die cavity that extends vertically into the interposer substrate, creating a stepped structure. This dimensional change allows the die to be positioned lower, effectively reducing the vertical distance that interconnects must span. By transitioning from a flat surface to a three-dimensional cavity structure, the patent reduces interconnect aspect ratio while maintaining high I/O density.
Solution Approach 2:
The die cavity is formed by removing material from the interposer substrate, creating a nested void space that accommodates the die. This nesting approach allows the die to be embedded within the interposer structure rather than sitting on the surface, reducing the vertical interconnect path length while maintaining compact packaging.
2Adaptability or versatility
If the die size is increased to provide more circuits, then the functionality increases, but the heat generation increases and becomes difficult to dissipate
Solution Approach 1:
The patent creates a localized cavity structure directly beneath the die to facilitate heat dissipation. By concentrating thermal management resources (the cavity space for thermal interface materials and heat sinks) specifically at the heat-generating die location, the patent effectively addresses thermal issues without compromising the increased functionality provided by larger die sizes.
3Manufacturing precision
If the vertical distance between die and package substrate is reduced, then the interconnect aspect ratio improves, but the package structure becomes more complex
Solution Approach 1:
The patent merges the die mounting function with the thermal management function by integrating the die cavity directly into the interposer substrate. This consolidation eliminates the need for separate thermal management components and simplifies the overall package structure while achieving reduced interconnect aspect ratios.
Data Source
AI summary
Interposer substrate with integrated step die cavity, and related integrated circuit (IC) packages and related fabrication methods. A die cavity integrated in an outer layer(s) of the interposer substrate provides room for a die to extend into the interposer substrate (e.g., to facilitate increased die height). Forming the die cavity in the outer layer(s) facilitates metal interconnects in an outer metallization layer of the interposer substrate being located adjacent to the die cavity can also enhance heat dissipation for the die extending into the die cavity. Forming the die cavity in the outer layer(s) of the interposer substrate also facilitates reduced distance between the interposer substrate and package substrate to facilitate reduced height vertical interconnects coupling the interposer substrate to the package substrate. This facilitates vertical interconnects with reduced aspect ratio and reduced pitch that can support dies with higher input/output (I/O) connection density.